GB2571573A

GB2571573A - Graphene and carbon nanostructure production

Info

Publication number: GB2571573A
Application number: GB1803418.1A
Authority: GB
Inventors: O'flynn Donal
Original assignee: Donal Oflynn
Current assignee: Donal Oflynn
Priority date: 2018-03-02
Filing date: 2018-03-02
Publication date: 2019-09-04
Also published as: GB201803418D0

Abstract

Apparatus (1) for producing graphene and/or carbon nanostructures includes a reactor vessel (2). The reactor vessel is configured to receive a growth substrate (3) for forming graphene and/or carbon nanostructures. The growth substrate extends to define a path (4, Figure 2), and a support layer (5) supporting the growth substrate. The reactor vessel also encloses a feedstock application system (6) configured to apply a carbon containing feedstock to an application area (7) of the growth substrate. The application area for the feedstock is controllably moveable along the path. The reactor vessel also encloses a heating system (9) configured to heat a heated area (10) of the growth substrate. The heated area is controllably moveable along the path. A method of forming graphene and/or carbon nanostructures using the apparatus is disclosed.

Description

Graphene and carbon nanostructure production

Field of the invention

The present invention relates to apparatus and methods for producing graphene and/or 5 other carbon nanostructures.

Background

Graphene and carbon nanostructures represent a class of materials which have attracted strong interest as a result of potential applications in, amongst other area, 10 electronics, energy storage, catalysis, filtration and, in the case of graphene, as a structural material.

Formation of graphene has been reported for a wide variety of different substrates, many of which are metallic. For example, see “Graphene film growth on polycrystalline 15 metals”, Edwards, Rebecca S. and Coleman, Karl S. (2013), Accounts of chemical research, 46 (1). pp. 23-30. In addition, synthesis of graphene and other forms of carbon nanostructures has been reported using molten salts, see for example “Salt melt synthesis of ceramics, semiconductors and carbon nanostructures”, Xiaofeng Liu, Nina Fechler and Markus Antonietti, Chem. Soc. Rev., 2013, 42, 8237. Synthesis of graphene, including a cuboidal form of graphene, has been reported using a soluble salt substrate, see “Direct Synthesis of Few-Layer Graphene on NaCl Crystals”, Liurong Shi et al, Small, Vol. 11, No. 47, pages 6302-6308, 2015.

In order to realise the potential applications of graphene or other carbon nanostructures for electronics, energy storage or mechanics, production of large quantities of high quality graphene or other carbon nanostructures will be needed. It has been suggested to perform batch processing or roll-to-roll processes using metal foils as growth substrates for graphene. However, conventionally the graphene has been obtained by etching the metal foils after graphene deposition, which is wasteful of materials and generates significant amounts of corrosive chemical waste. This has led to interest in alternative methods of removing graphene from metal foils coated in batch or roll-to-roll processes.

For example, WO 2015/196066 A2 describes processes for transferring graphene layers 35 to a flexible substrate based on preferential adhesion of certain thin metallic films to

- 2 graphene followed by lamination of the metallized graphene layers to a flexible target substrate in a process compatible with roll-to-roll manufacturing.

US 2017/0080696 Ai describes a method which includes forming at least one layer of material on at least part of a surface of a first substrate, wherein a first surface of the at least one layer of material is in contact with the first substrate thereby defining an interface. The method includes attaching a second substrate to a second surface of the at least one layer of material, forming bubbles at the interface. The method includes applying mechanical force whereby the second substrate and the at least one layer of 10 material are jointly separated from the first substrate.

Alternatives to production on solid metal foils have been suggested. For example, US 2015/0122659 Ai describes a method of producing graphene from a liquid metal matrix.

Similarly, carbon nanostructures have been produced using powdered metals, with removal of the carbon nanostructures using similar etching processes. The inefficiency and chemical waste generated by such etching processes are an impediment to producing large volumes of carbon nanostructures for use in energy storage applications.

Summary

According to a first aspect of the invention there is provided an apparatus for producing graphene and/or carbon nanostructures which includes a reactor vessel. The reactor 25 vessel is configured to receive a growth substrate for forming graphene and/or carbon nanostructures. The growth substrate extends to define a path. The reactor vessel is also configured to receive a support layer supporting the growth substrate. The reactor vessel encloses a feedstock application system configured to apply a carbon containing feedstock to an application area of the growth substrate. The application area for the 30 carbon containing feedstock is controllably moveable along the path. The reactor vessel also includes a heating system configured to heat a heated area of the growth substrate. The heated area is controllably moveable along the path.

Carbon nanostructures may include one or more of graphene flakes, graphene powder, 35 cuboidal graphene, graphene nanoscrolls, nanodiamonds, carbon nanotubes, carbon nanowhiskers, and so forth.

-3The growth substrate may include a metallic film.

The growth substrate may include a salt, an oxosalt, a metal halide or an ionic liquid.

The support layer may be formed of a material having a higher melting point than the growth substrate.

The support layer may include a recessed channel. The growth substrate may be supported within the recessed channel.

The apparatus may include a metallic adhesion layer provided between the support layer and the growth substrate.

The feedstock application system may include a mobile feedstock applicator mounted to a linear guideway.

The feedstock application system may include a plurality of static feedstock outlets spaced along the path. Each static feedstock outlet may be configured to apply the 20 carbon containing feedstock to a corresponding application area of the growth substrate when the static feedstock outlet is actuated. The static feedstock outlets may be configured to be actuated according to a sequence such that an active application area is controllably moveable along the path.

The heating system may include a mobile heating element mounted to a linear guideway.

The heating system may include a plurality of static heating elements spaced along the path. Each static heating element may be configured to heat a corresponding heated 30 area of the growth substrate. The static heating elements may be configured to be actuated according to a sequence such that an active heated area is controllably moveable along the path.

The heating system may include a radiation emitting system configured to emit 35 radiation energy. The heating system may include at least one reflection element

-4configured to redirect the radiation energy to heat a heated area of the growth substrate.

The at least one reflection element may include a mirror configured to be controllably 5 moveable along the path.

The at least one reflection element may include a plurality of mirrors. Each mirror may be configured to be actuated to cause the mirror to redirect radiation energy to a corresponding heated area of the growth substrate. The plurality of mirrors may be 10 configured to be actuated according to a sequence such that an active heated area is controllably moveable along the path.

The apparatus may also include a cooling system enclosed within the reactor vessel and configured to cool a cooled area of the growth substrate. The cooled area may be 15 controllably moveable along the path.

The cooling system may include a mobile cooling element mounted to a linear guideway.

The cooling system may include a plurality of static cooling elements spaced along the path. Each static cooling element may be configured to cool a corresponding cooled area of the growth substrate. The static cooling elements may be configured to be actuated according to a sequence such that an active cooled area is controllably moveable along the path.

The apparatus may also include a collection system enclosed within the reactor vessel and configured to remove a layer of graphene and/or carbon nanostructures formed on the growth substrate.

The collection system may be configured to transfer the layer of graphene and/or carbon nanostructures to a capture plate.

The reactor vessel may include a rotating load lock configured to rotate the capture plate to the exterior of the reactor vessel to permit extraction of the removed layer of 35 graphene and/or carbon nanostructures.

-5The path may define a closed loop.

The reactor vessel may enclose the growth substrate and the support layer.

The reactor vessel may be further configured to receive one or more additional growth substrates. Each additional growth substrate may be supported on a corresponding additional support layer. Each additional growth substrate may extend to define a corresponding additional path.

The apparatus may also include, enclosed within the reactor vessel, one or more additional growth substrates. Each additional growth substrate may be supported on a corresponding additional support layer. Each additional growth substrate may extend to define a corresponding additional path.

The apparatus may include a separate feedstock application system and a separate heating system corresponding to each additional path.

The feedstock application system and the heating system may be configured such that the application area and the heated area are each controllably moveable along the path 20 and along each additional path.

The reactor vessel may operate at substantially ambient pressure. The reactor vessel may operate under vacuum conditions. The reactor vessel may operate under ultrahigh vacuum conditions. The reactor vessel maybe backfilled with an inert gas. The 25 reactor vessel may be backfilled with nitrogen or argon.

The growth substrate may include one or more of copper, nickel, cobalt, iron, indium, chromium, titanium, tantalum, gallium, gallium nitride, tin, rhenium, ruthenium, platinum, germanium, palladium or gold.

The growth substrate may include an alloy of two or more of copper, nickel, cobalt, iron, indium, chromium, titanium, tantalum, gallium, gallium nitride, tin, rhenium, ruthenium, platinum, germanium, palladium or gold. An alloy used for the growth substrate may have a composition chosen to control the melting point of the alloy to 35 above or below a desired process temperature for depositing graphene and/or carbon nanostructures.

-6The growth substrate may substantially consist of one of copper, nickel, cobalt, iron, indium, chromium, titanium, tantalum, gallium, gallium nitride, tin, rhenium, ruthenium, platinum, germanium, palladium or gold.

The growth substrate may include one or more metal halide salts. Metal halide salts may include metal-chlorine salts such as, for example, lithium chloride, sodium chloride, potassium chloride, aluminium chloride, zinc chloride and so forth. Metal halide salts may include metal-fluorine salts such as, for example, lithium fluoride, sodium fluoride, potassium fluoride and so forth. Metal halide salts may include metaliodine salts such as, for example, lithium iodide, sodium iodide, potassium iodide and so forth.

The growth substrate may include one or more oxosalts such as, for example, hydroxides, sulphates, carbonates and so forth. The growth substrate may include lithium hydroxide, sodium hydroxide, potassium hydroxide and so forth. The growth substrate may include lithium sulphate, sodium sulphate, potassium sulphate, and so forth. The growth substrate may include lithium carbonate, sodium carbonate, potassium carbonate and so forth.

The growth substrate may include a mixture of one or more salts or ionic liquids chosen to control the melting point of the mixture to above or below a desired process temperature for depositing graphene and/or carbon nanostructures.

The growth substrate may facilitate graphene and/or carbon nanostructure growth via a surface catalysis mechanism. The growth substrate may facilitate graphene and/or carbon nanostructure growth via a precipitation or segregation mechanism. The growth substrate may facilitate graphene and/or carbon nanostructure growth in a liquid phase mechanism.

The growth substrate may have a thickness of up to 5 nm. The growth substrate may have a thickness of up to 10 nm. The growth substrate may have a thickness of up to 25 nm. The growth substrate may have a thickness of up to 50 nm. The growth substrate may have a thickness of up to too nm. The growth substrate may have a thickness of 35 up to 500 nm. The growth substrate may have a thickness of up to 1 pm. The growth substrate may have a thickness of up to 10 pm. The growth substrate may have a

-Ίthickness of up to 25 pm. The growth substrate may have a thickness of up to 50 pm.

The growth substrate may have a thickness of up to too pm. The growth substrate may have a thickness of up to 500 pm. The growth substrate may have a thickness of up to 1000 pm.

The growth substrate may have a thickness of between 5 nm and 10 nm, between 10 nm and 25 nm, between 25 nm and 50 nm, between 50 nm and too nm, between too nm and 500 nm, between 500 nm and 1 pm, between 1 pm and 10 pm, between 10 pm and 25 pm, between 25 pm and 50 pm, between 50 pm and too pm, between too pm and 10 500 pm, or between 500 pm and 1000 pm.

The growth substrate may be solid at room temperature and solid at a processing temperature used for forming graphene and/or carbon nanostructures. The growth substrate may be solid at room temperature and liquid or partially liquid at a processing temperature used for forming graphene and/or carbon nanostructures.

The support layer may be formed of quartz. The support layer may be formed of fused silica. The support layer may be formed of tungsten.

The surface of the growth substrate may be flush with the surface of the support layer outside of the recessed channel.

The carbon containing feedstock may include a solid. The carbon containing feedstock may include a liquid. The carbon containing feedstock may include a gas. The carbon 25 containing feedstock may include a paste or an ink.

The carbon containing feedstock may include one or more of acetylene, ethylene, methane, benzene or any other suitable carbon containing gases known for production of graphene and/or carbon nanostructures.

The carbon containing feedstock may include amorphous carbon, carbon black, glucose, organic polymers, graphite, or any other suitable solid or liquid substance known for production of graphene and/or carbon nanostructures.

-8The application area and the heated area may at least partially overlap. The apparatus maybe configured such that the application area moves along the path in advance of the heated area.

The heating system may comprise an electromagnetic induction heating element. The heating system may comprise a laser. The heating system may comprise an optical flash lamp. The heating system may comprise a microwave heating element. The heating system may comprise a resistive heating element.

The heating system may be configured to heat the heated area to a temperature within a range between 15 °C and 2000 °C. The heating system may be configured to heat the heated area to a temperature within a range between 50 °C and 2000 °C. The heating system may be configured to heat the heated area to a temperature within a range between too °C and 2000 °C. The heating system maybe configured to heat the heated area to a temperature within a range between 500 °C and 2000 °C. The heating system may be configured to heat the heated area to a temperature within a range between 1000 °C and 2000 °C.

The heating system maybe configured to at least partially melt the growth substrate within the heated area. The heating system may be configured so as to avoid melting the support layer. The heating system may be configured to selectively heat the growth substrate.

The radiation emitting system may be a microwave emission system. A microwave emission system may include one or more microwave lasers. The radiation emitting system may be an infra-red emitting system. An infra-red emitting system may include one or more infra-red lasers. The radiation emitting system may be a visible light emitting system. A visible light emitting system may include one or more infra-red lasers.

The at least one reflection element may include one or more mirrors. The at least one reflection element may include one or more ultra-fast mirrors. Mirrors forming part of a reflection element may be concave. Mirrors forming part of a reflection element may be convex.

-9The radiation emitting system may be tuned to an absorbance of the carbon-containing feedstock. The radiation emitting system may be tuned to an absorbance of the growth substrate. The radiation emitting system may be tuned to an absorbance of the support layer. The radiation emitting system may be tuned to a transmission window of the 5 support layer.

The radiation emitting system may take the form of a microwave emitter coupled to a microwave waveguide system. The microwave waveguide system may include outlets which may individually actuated to heat a corresponding heated area of the growth 10 substrate.

The cooling system may comprise one or more gas vents configured to direct a cooling gas at a corresponding cooled area of the growth substrate. The cooling system may be configured to apply a cooling gas at substantially ambient temperature. The cooling 15 system may be configured to apply a cooling gas having a temperature within a range between 0 °C and 40 °C. The cooling system may be configured to apply a cooling gas having a temperature within a range between 15 °C and 30 °C.

The cooling system maybe configured to apply a cooling gas at cryogenic temperatures.

The cooling gas may comprise an inert gas. The cooling gas may comprise argon. The cooling gas may comprise nitrogen. The cooling gas may comprise boron for doping a layer of graphene and/or carbon nanostructures deposited on the growth substrate.

The cooling gas may comprise hydrogen for doping a layer of graphene and/or carbon 25 nanostructures deposited on the growth substrate.

The cooling system maybe configured to cause precipitation of graphene and/or carbon nanostructures on the cooled area of the growth substrate.

The cooling system may be configured to control a number of graphene layers formed on the surface of the growth substrate.

The cooling system may be configured to control a yield of carbon nanostructures formed on the surface of the growth substrate. The cooling system may be configured 35 to control one or more of the size, quantity and/or morphology of carbon nanostructures formed on the surface of the growth substrate.

- 10 The cooling system may be configured to cool the cooled area to a given temperature within a range from 15 °C to 1000 °C. The cooling system may be configured to cool the cooled area to a given temperature within a range from 50 °C to 1000 °C. The cooling system may be configured to cool the cooled area to a given temperature within a range from 100 °C to 1000 °C. The cooling system may be configured to cool the cooled area to a given temperature within a range from 200 °C to 1000 °C. The cooling system maybe configured to cool the cooled area to a given temperature within a range from 500 °C to 1000 °C.

The collection system may be configured to directly peel the layer of graphene and/or carbon nanostructures off the growth substrate. The collection system may be configured to peel the layer of graphene and/or carbon nanostructures off the growth substrate without using any supporting substrate. The collection system may be 15 configured to skim a layer of graphene and/or carbon nanostructures off the surface of a molten growth substrate.

The collection system may comprise an exfoliation roller configured to exfoliate a graphene layer from the growth substrate using and an adhesive substrate.

The collection system does not remove the growth substrate from the support layer.

The collection system may include a laser configured to introduce a discontinuity into the layer of graphene and/or carbon nanostructures to assist in removal of the layer of 25 graphene and/or carbon nanostructures from the growth substrate.

The laser may be configured to scission the layer of graphene and/or carbon nanostructures into strips running parallel to the path. The laser may be a solid-state laser. The laser may be a dye laser. The laser may be a gas laser. The laser may be a laser diode. The laser may be an excimer laser. The laser may be a red laser diode. The laser may be an infrared laser diode.

The apparatus may include a separate cooling system corresponding to each additional path. The apparatus may include a separate collection system corresponding to each 35 additional path.

- 11 The cooling system may be configured to be controllably moveable along the path and along each additional path. The collection system maybe configured to be controllably moveable along the path and along each additional path.

One or more additional growth substrates may be provided which define additional paths which are parallel to and spaced horizontally from the path. One or more additional growth substrates maybe provided which define additional paths which are parallel to and stacked vertically with the path.

According to a second aspect of the invention there is provided a method of producing graphene and/or carbon nanostructures inside a reactor vessel which is configured to receive a growth substrate for forming graphene and/or carbon nanostructures and which extends to define a path and a support layer supporting the growth substrate. The method includes applying a carbon containing feedstock to an application area of 15 the growth substrate. The method also includes heating a heated area of the growth substrate. The method also includes controlling the application area and the heated area to move along the path.

The method may include features corresponding to any feature of the apparatus.

- 12 Brief Description of the Drawings

Certain embodiments of the present invention will now be described, by way of example, with reference to the accompanying drawings in which:

Figure 1 illustrates a portion of an apparatus for producing graphene and/or carbon nanostructures;

Figure 2 is a plan view of a portion of an apparatus for producing graphene and/or carbon nanostructures shown in Figure 1;

Figure 3 is a process flow diagram of a method of producing graphene and/or carbon nanostructures;

io Figure 4 to 8 are cross-sectional views illustrating different configurations of a growth substrate and a support layer;

Figure 9 illustrates a mobile feedstock applicator;

Figure 10 illustrates an example of a mobile feedstock applicator shown in Figure 9;

Figure 11 illustrates a portion of a feedstock application system including a number of 15 static feedstock outlets;

Figure 12 is a cross-sectional view of the feedstock application system shown in Figure 11;

Figure 13 illustrates a mobile heating element;

Figure 14 illustrates a portion of a heating system which includes a number of static heating elements spaced along a path;

Figure 15 illustrates an example of the heating system shown in Figure 14;

Figure 16 illustrates a heating system which includes a radiation source and a number of actuatable reflection elements spaced along a path;

Figure 17 illustrates a heating system which includes a radiation source and a mobile 25 reflection element;

Figure 18 illustrates using concave reflection elements in the heating system shown in

Figure 16;

Figure 19 illustrates using convex reflection elements in the heating system shown in Figure 16;

Figure 20 illustrates an example of forming a layer of graphene and/or carbon nanostructures;

Figure 21 illustrates a configurable waveguide system for guiding microwave radiation;

Figure 22 illustrates a mobile cooling element;

Figure 23 illustrates a portion of a cooling system which includes a number of static cooling elements spaced along a path;

Figure 24 is a cross-sectional view of the cooling system shown in Figure 23;

-13Figure 25 illustrates a portion of a first exemplary apparatus for producing graphene and/or carbon nanostructures;

Figure 26 illustrates a portion of a second exemplary apparatus for producing graphene and/or carbon nanostructures;

Figure 27 illustrates a portion of a third exemplary apparatus for producing graphene and/or carbon nanostructures;

Figure 28 is a cross-sectional view of the third exemplary apparatus for producing graphene and/or carbon nanostructures;

Figure 29 illustrates a portion of a fourth exemplary apparatus for producing graphene 10 and/or carbon nanostructures;

Figure 30 is a cross-sectional view of the fourth exemplary apparatus for producing graphene and/or carbon nanostructures;

Figure 31 illustrates a portion of a fifth exemplary apparatus for producing graphene and/or carbon nanostructures;

Figure 32 is a cross-sectional view of the fifth exemplary apparatus for producing graphene and/or carbon nanostructures;

Figure 33 illustrates a portion of a sixth exemplaiy apparatus for producing graphene and/or carbon nanostructures;

Figure 34 is a cross-sectional view of the sixth exemplary apparatus for producing graphene and/or carbon nanostructures;

Figure 35 illustrates a collection system configured to peel a layer of graphene and/or carbon nanostructures from a growth substrate;

Figure 36 illustrates a second collection system configured to exfoliate a layer of graphene and/or carbon nanostructures from a growth substrate;

Figure 37 illustrates a transfer system for transferring a layer of graphene and/or carbon nanostructures from a growth substrate to a capture plate;

Figure 38 is a side view of the transfer system shown in Figure 37; Figures 39 and 40 illustrate extracting a layer of graphene and/or carbon nanostructures from a reactor vessel using a rotating load lock;

Figures 41 and 42 are plan views of closed loop paths defined by a growth substrate; Figures 43 and 44 are plan views of apparatus including multiple, parallel and horizontally spaced growth substrates;

Figure 45 illustrates a modified collection system which includes a laser; and Figure 46 illustrates vertical stacking of growth substrates.

-14Detailed Description of Certain Embodiments

In the following, like parts are denoted by like reference numbers.

Apparatus for producing graphene and/or carbon nanostructures

Referring to Figure 1 and 2, apparatus 1 for producing graphene and/or carbon nanostructures is shown.

Carbon nanostructures may include one or more of graphene flakes , graphene powder, cuboidal graphene, graphene nanoscrolls, nanodiamonds, carbon nanotubes, carbon io nanowhiskers, and so forth.

Large, contiguous sheets of mono-layer or few-layer graphene may be of interest for applications including electronics, energy harvesting or storage, catalysis, structural mechanics and so forth. Carbon nanostructures may be of interest for applications 15 including energy harvesting or storage, catalysis, filtering and so forth.

The apparatus includes a reactor vessel 2. The reactor vessel 2 encloses, or is configured to receive, a growth substrate 3 for forming graphene and/or carbon nanostructures. The growth substrate 3 extends to define a path 4, and a support layer 20 5 supports the growth substrate 3. For example, the growth substrate 3 and support layer 5 need not be integrally formed with the reactor vessel 2, and instead may be removable to allow for replacement or cycling of the growth substrate 3 used by the apparatus 1. The reactor vessel 2 encloses a feedstock application system 6 configured to apply a carbon containing feedstock to an application area 7 of the growth substrate 25 3. The application area 7 for the feedstock is controllably moveable in a direction 8 along the path 4. The reactor vessel 2 encloses a heating system 9 configured to heat a heated area 10 of the growth substrate 3. The heated area 10 is controllably moveable in the direction 8 along the path 4.

The path 4 defined by the growth substrate 3 may be up to hundreds of metres long and up to tens of metres wide. The growth substrate 3 acts as a catalyst for growth of a layer 11 of graphene and/or carbon nanostructures, and may also function to promote decatenation of the carbon containing feedstock. The layer 11 may take the form of monolayer graphene or multilayer graphene, depending on the specific operating parameters of the apparatus 1. Depending on the specific operating parameters of the apparatus 1, the layer 11 may take the form of a variety of carbon nanostructures such

-ι₅as, for example, graphene flakes, graphene powder, cuboidal graphene, graphene nanoscrolls, nanodiamonds, carbon nanotubes, carbon nanowhiskers, and so forth.

The path 4 may be configured as a linear path or as a closed loop. In some examples the application area 7 and heated area 10 may perform a single pass along the path 4.

In other examples the application area 7 and heated area 10 may perform multiple passes along the path 4. In some examples, each time the application area 7 and heated area 10 pass a point on the growth substrate 3, an additional monolayer or multilayer of graphene may be deposited. In alternative examples, each time the application area 7 10 and heated area 10 pass a point on the growth substrate 3, an additional layer of carbon nanostructures maybe formed, or previously deposited carbon nanostructures maybe extended or developed.

By using a moving application area 7 and heated area 10, the apparatus 1 may produce 15 layers 11 of graphene and/or carbon nanostructures across large areas in a way which is efficient in both the quantities of carbon-containing feedstock applied and also in the amount of energy which is used. By moving the application area 7 and heated area 10, the growth substrate 3 may be provided by a broader range of materials as compared to a roll-to-roll process. In particular, the growth substrate 3 need not be mechanically robust and may be extremely thin. Furthermore, the growth substrate 3 may actually be melted for production of graphene and/or carbon nanostructures, which would not be practical in a roll-to-roll process.

The apparatus 1 may optionally include a cooling system 12 enclosed within the reactor 25 vessel 2 and configured to cool a cooled area 13 of the growth substrate 3. The cooled area 13 may be controllably moveable in the direction 8 along the path 4.

The apparatus 1 may optionally include a collection system 14 enclosed within the reactor vessel 2 and configured to remove a layer 11 of graphene and/or carbon nanostructures formed on the growth substrate 3.

The feedstock application system 6 may include a mobile feedstock applicator 15 (Figure 9) mounted to a linear guideway 16 (Figure 9) which follows the path 4. Additionally or alternatively, the feedstock application system may include a number of 35 static feedstock outlets 17 (Figure 11) spaced along the path 4.

-16The heating system 9 may include a mobile heating element 18 (Figure 13) mounted to a linear guideway 16 (Figure 13) which follows the path 4. Additionally or alternatively, the heating system 9 may include a number of static heating elements 19 (Figure 14) spaced along the path 4.

The apparatus 1 may be configured such that the application area 7 and the heated area 10 may at least partially overlap. Alternatively, the apparatus 1 maybe configured such that the application area 7 moves along the path 4 in advance of the heated area 10.

When present, the cooling system 12 may include a mobile cooling element 20 (Figure 22) mounted to a linear guideway 16 (Figure 22) which follows the path 4. Additionally or alternatively, the cooling system 12 may include a number of static cooling elements 21 spaced along the path 4.

The collection system 14 may be configured to transfer the layer 11 of graphene and/or carbon nanostructures to a capture plate 22 (Figure 37).

Depending upon the material used for the growth substrate 3, the reactor vessel 2 may operate at substantially ambient pressure. For example, the apparatus 1 may be 20 configured to produce a layer 11 of graphene and/or carbon nanostructures using ambient pressure chemical vapour deposition process. In other examples, the reactor vessel 2 may operate under vacuum conditions or ultra-high vacuum conditions. The reactor vessel 2 may be backfilled with an inert gas to prevent oxidation of the carbon containing feedstock, the layer 11 of graphene and/or carbon nanostructures and/or the 25 growth substrate. The inert gas may be, for example, nitrogen or argon. In some examples, argon may be preferred to avoid nitrogen doping of produced layers 11 of graphene and/or carbon nanostructures, and/or nitriding of the growth substrate 3. However, in other examples nitrogen doping of layers 11 of graphene and/or carbon nanostructures may be desired, such that the reactor vessel 2 should be filled to include 30 a partial pressure of nitrogen.

The reactor vessel 2 should be as contained as possible to maximize the percentage of carbon containing feedstock that is decatenated into carbon and hydrogen. The localised application and heating of the carbon containing feedstock may serve to avoid 35 the need for heating a large thermal mass of carbon containing feedstock, which may improve efficiency of the apparatus 1 overall.

-17The growth substrate 3 and the support layer 5 may form a simple layered structure. The growth substrate 3 may take the form of a metallic film. The growth substrate 3 may take the form of a salt, an oxosalt, a metal halide or a high temperature ionic liquid. Depending upon the particular material used to form the growth substrate 3, the growth substrate 3 may facilitate growth of the layer 11 of graphene and/or carbon nanostructures via a surface catalysis mechanism, via a precipitation or segregation mechanism, or via a liquid phase mechanism.

In general, the growth substrate 3 may include, or be formed from, any material known to be suitable for catalysing formation of a layer 11 of graphene and/or carbon nanostructures such as, for example, copper, nickel, cobalt, iron, indium, chromium, titanium, tantalum, gallium, gallium nitride, tin, rhenium, ruthenium, platinum, germanium, palladium, gold and so forth. Alternatively, the growth substrate 3 may be 15 formed from an alloy of two or more metallic elements.

In other examples, the growth substrate 3 may include one or more metal halide salts such as, for example, lithium chloride, sodium chloride, potassium chloride, aluminium chloride, zinc chloride, lithium fluoride, sodium fluoride, potassium fluoride, lithium 20 iodide, sodium iodide, potassium iodide, and so forth. The growth substrate 3 may include one or more oxosalts such as, for example, hydroxides, sulphates, carbonates and so forth. The growth substrate 3 may include a mixture of one or more salts or ionic liquids chosen to control the melting point of the mixture to above or below a desired process temperature for depositing graphene and/or carbon nanostructures.

For example, if a relatively low temperature process is desired, a eutectic composition may be used.

The growth substrate 3 may have a thickness in the range from 5 nm to 1000 pm. The specific thickness chosen may depend upon the material used to form the growth substrate 3. For example, some metallic materials exhibit preferential crystallographic orientations in thin films. Alternatively, for some growth substrate 3 materials, grain boundaries may be a more significant factor, in which case a thicker growth substrate 3 may allow for a greater extend of grain growth upon annealing. When a salt-based growth substrate is used which is not melted by the heated area 10, the size distribution 35 of salt crystals may influence the yield and morphology of graphene and/or carbon nanostructures which are formed. Possible ranges for the thickness of the growth

-18substrate 3 have been enumerated hereinbefore, and the preferred thickness range(s) for a given growth substrate 3 material may be obtained by consulting the literature for that material.

The support layer 5 is preferably formed of a material having a higher melting point than the growth substrate 3. For some growth substrate 3 materials having relatively high melting points, a higher melting point may be unnecessary, for example if the growth substrate 3 is formed of tantalum, tungsten or another refractory metal. The support layer 5 should be chemically inert, or substantially chemically inert with respect to the carbon containing feedstock. Suitable examples of materials for forming the support layer include, for example, quartz, fused silica, tungsten, and so forth.

The heating system 9 should be configured to heat the heated area 10 to a temperature within a range between 15 °C and 2000 °C. The specific temperature to which the heated area 10 is heated will depend upon material forming the growth substrate 3. The heating system 9 may be configured to at least partially melt the growth substrate 3 within the heated area 10. The heating system 9 should avoid heating the heated area 10 excessively, to avoid melting the support layer 5, dissociating a molten salt or boiling a molten salt. The heating system 9 maybe configured to selectively heat the growth substrate 3 without directly heating the support layer 5.

Method of producing graphene and/or carbon nanostructures

Referring also to Figure 3, a process-flow diagram of a method of producing graphene and/or carbon nanostructures is shown. The method is conducted using the apparatus 25 1.

As the application area 7 corresponding to the feedstock application system 6 passes a given point of the growth substrate 3, the feedstock application system 6 applies the carbon-containing feedstock (step Si).

The application area 7 continues along the path 4 and the heated area 10 corresponding to the heating system 9 then moves over the given point of the growth substrate 3 (step S2). The heating system 9 heats the growth substrate 3, support layer 5 and/or carbon containing feedstock, which may cause the growth substrate 3 to catalyse decomposition of the carbon-containing feedstock into carbon hydrogen and other

-19constituents. In some examples, the carbon-containing feedstock maybe decomposed by heating alone.

When the growth substrate 3 forms a layer 11 of graphene and/or carbon nanostructures by surface catalysis, the layer 11 may be formed at this stage. When the growth substrate 3 forms a layer 11 of graphene and/or carbon nanostructures by precipitation or segregation from solid solution or upon solidification of a melt, the layer 11 may be formed as the graphene growth substrate 3 cools.

Natural cooling of the growth substrate 3 is expected to be rapid because of the lower thermal mass of a thin growth substrate 3 of the order of nm or pm thickness.

However, in some examples, the optional cooling system 12 maybe included to provide more rapid and/or controllable cooling profiles. As the cooled area 13 passes the given 15 point, the growth substrate 3 is rapidly cooled (step S3).

Optionally, a layer 11 of graphene and/or carbon nanostructures formed on the growth substrate 3 may be trimmed or cut into one or more extended ribbons using a laser (step S4). Further details are discussed hereinafter (Figure 45).

Optionally, a layer 11 of graphene and/or carbon nanostructures formed on the growth substrate 3 is peeled or exfoliated by a collection system 14, 71 (Figure 36) (step S5). Alternatively, the growth substrate 3 may remain molten whilst a layer 11 of graphene and/or carbon nanostructures may be skimmed off the liquid surface by the collection 25 system 14.

Optionally, a layer 11 of graphene and/or carbon nanostructures peeled, exfoliated or skimmed off the growth substrate 3 is transferred to a capture plate (Figure 37) (step S6), and the capture plate 22 is cycled outside the controlled environment of the 30 reactor vessel 2 to allow the layer 11 of graphene and/or carbon nanostructures to be collected (step S7).

If further layers 11 of graphene and/or carbon nanostructures are desired, the application area 7 and heated area 10 may be controlled to return to the beginning of 35 the path 4 and start again, or to traverse the path 4 in reverse (step S8).

- 20 If a previously deposited layer 11 of graphene and/or carbon nanostructures has been peeled, exfoliated or skimmed off the growth substrate 3, then a fresh layer 11 of graphene and/or carbon nanostructures may be deposited. Alternatively, if a previously deposited layer 11 of graphene and/or carbon nanostructures has not been peeled or exfoliated off the growth substrate 3, the previously deposited layer 11 of graphene and/or carbon nanostructures may be built up by a further monolayer or multi-layer of graphene, by deposition of further carbon nanostructures, or by growth of previously deposited carbon nanostructures.

Examples of growth substrate configurations

Referring also to Figure 4, a second example 23 of a growth substrate 3 and support layer 5 configuration is shown.

In the second example 23, a metallic adhesion layer 24 is provided between the support 15 layer 5 and the growth substrate 3. The metallic adhesion layer 24 may serve to improve the binding of the growth substrate 3 to the support layer 5 and prevent delamination of the growth substrate 3 on peeling or exfoliating a deposited layer 11 of graphene and/or carbon nanostructures. Additionally or alternatively, a metallic adhesion layer 24 may serve to relieve thermal stresses between the growth substrate 3 20 and the support layer 5 during repeated cycles of heating and cooling, for example, the metallic adhesion layer 24 may have a thermal expansion coefficient which is intermediate between the support layer 5 and the growth substrate 3. Additionally or alternatively, a metallic adhesion layer 24 may serve as a wetting layer to prevent beading in processes during which the growth substrate 3 is required to melt, or 25 incidentally melts, during passage of the heated zone 10. Additionally or alternatively, a metallic adhesion layer 24 may include grain boundaries, inclusions and/or surface texturing which serve to influence or control nucleation of, for example, a solidifying molten salt so as to control a distribution of crystal sizes.

Referring also to Figure 5, a third example 25 of a growth substrate 3 and support layer 5 configuration is shown.

In the third example 25, the support layer 5 includes a recessed channel 26 having a rectangular cross-section. The growth substrate 3 is supported and contained within 35 the recessed channel 26. Preferably, the surface 27 of the growth substrate 27 is flush with an uppermost surface 28 of the support layer 5 outside of the recessed channel 26.

- 21 Referring also to Figure 6, a fourth example 29 of a growth substrate 3 and support layer 5 configuration is shown.

In the fourth example 29, a metallic adhesion layer 24 is deposited in a rectangular recessed channel 26 of the support layer 4. The growth substrate 3 is deposited over the metallic adhesion layer 24.

Referring also to Figure 7, a fifth example 30 of a growth substrate 3 and support layer 10 5 configuration is shown.

A recessed channel in the support layer 5 need not be rectangular and may instead have any suitable cross-section. For example, in the fifth example 30, the support layer 5 includes a recessed channel 31 having a cross-section corresponding to a portion of a circle. A curved cross-section of recessed channel 31 may help to retain a flush surface between the growth substrate 3 and the support layer 5 in examples in which the growth substrate 3 is intentionally, or unintentionally, melted during the passage of the heated zone 10.

Referring also to Figure 8, a sixth example 32 of a growth substrate 3 and support layer 5 configuration is shown.

A metallic adhesion layer 24 may be applied to any cross-section of recessed channel

31. In the sixth example 32, a metallic adhesion layer 24 may be deposited within a 25 recessed channel 31 having a cross-section corresponding to a portion of a circle. The growth substrate 3 is then deposited over the metallic adhesion layer 24.

Any of the examples of a growth substrate 3 as illustrated in Figure 1 or any of Figures 4 to 8 may be used with any apparatus 1 described hereinbefore or hereinafter.

Feedstock application system

Referring also to Figure 9, the feedstock application system 6 may include a mobile feedstock applicator 15 mounted to a linear guideway 16.

The linear guideway 16 may take the form of one or more rails or other suitable guiding structures which follow the path 4 defined by the growth substrate 3. The linear

- 22 guideway 16 is enclosed within the reactor vessel 2. The linear guideway 16 may take the form of one or more rails disposed above and/or to either side of the growth substrate 3.

Movement of the mobile feedstock applicator 15 in the direction 8 along the path 4 may be provided by mechanisms integrated with the mobile feedstock applicator 15 and engaged with the linear guideway 16. Alternatively, the mobile feedstock applicator 15 maybe connected to a cord or chain which is supported within or adjacent to the linear guideway 16 and free to move with respect to the linear guideway 16. Examples of mechanisms for propelling the mobile feedstock applicator 15 include, but are not limited to, re-circulating rolling elements (not shown) located between the linear guideway 16 and a bearing block forming part of the mobile feedstock applicator 15, as well as linear synchronous motors (not shown) and, for high speeds, a linear induction motor (not shown).

The carbon containing feedstock may include a solid, a liquid, a gas, an ink, a paste, a powder and so forth.

For example, the carbon containing feedstock may be a gas and the mobile feedstock applicator 15 may take the form of one or more nozzles or outlets 33 (Figure 10) which direct gaseous carbon containing feedstock at the surface 27 of the growth substrate 3. In some examples, gaseous carbon containing feedstock may be cooled before dispensing to promote adsorption to surface 27 of the growth substrate 3, leaving a feedstock layer 34 adsorbed on the surface 27. In other examples, the heated area 10 may be immediately behind, or overlap with, the application area 7. Suitable gaseous carbon containing feedstocks may include one or more of acetylene, ethylene, methane, benzene or any other suitable carbon containing gases known to be useable for production of graphene and/or carbon nanostructures.

In other examples, the carbon containing feedstock may be a liquid and the mobile feedstock applicator 15 may take the form of one or more nozzles or outlets 33 (Figure

10) which discharge liquid carbon containing feedstock at the surface 27 of the growth substrate 3, either as a continuous stream of liquid feedstock or as spray of droplets. The liquid carbon containing feedstock may form a feedstock layer 34 on the surface 27 as the application area 7 moves along the path 4. Nozzles or outlets 33 (Figure 10) may also be used to apply carbon containing feedstock in the form or an ink comprising

-23carbon containing particles suspended in a solvent. A solvent is preferably an organic liquid, since aqueous inks may typically be unsuitable due to adverse chemical reactions such as oxidation.

Carbon containing feedstock in a liquid form may be applied in a variety of ways such as, for example, using a roller (not shown), an ink-jet printing head arrangement (not shown) or any other printing mechanism suitable for applying inks or liquids across a relatively large, continuous area. The mobile feedstock applicator 15 may include a doctor blade (not shown) to accurately control the thickness of a feedstock layer 34 left 10 behind when the application area 7 moves on along the path 4. Carbon containing pastes may also be applied using a mobile feedstock applicator 15 in the form of a roller (not shown) and doctor blade (not shown) arrangement.

In still other examples, the carbon containing feedstock may be solid, for example a powder including fine particles of amorphous carbon, carbon black, glucose or organic polymers. Solid powders may be applied to form an even, continuous feedstock layer 34 on the surface 27 of the growth substrate 3 using, for example, a hopper (and roller arrangement (not shown). Electrostatic attraction and transfer methods used for laser printing of controlled layers of toner may be readily adapted to applying layers of powdered carbon containing feedstock to the growth substrate 3. Indeed, laser printing toners are frequently carbon containing powders which may provide suitable feedstock for some examples of the apparatus 1. The application would be relatively simplified compared to a laser printer, since patterning of charges on a transfer roller (not shown) would not be needed for a uniform feedstock layer 34. For example, a charged transfer roller (not shown) may adhere a layer of powdered feedstock from a supply hopper, before transferring the powder to the surface 27. The surface 27 may be charged by applying a potential to a conductive growth substrate 3, or to electrodes (not shown) disposed beneath the support layer 5.

The hereinbefore described examples are not intended to be limiting. In general, the mobile feedstock applicator 15 may take the form of any mechanism which is capable of discharging, applying, printing or otherwise depositing a suitable carbon containing feedstock to the application area 7.

Referring also to Figure 10, an example of a mobile feedstock applicator 15 is shown which includes one or more outlets or nozzles 33.

-24When the path extends in a first direction, x and has a thickness in a third direction, z, a mobile feedstock applicator 15 may include a number of nozzles 33 spaced in a second, width direction y to ensure an even application of gaseous or liquid carbon containing feedstock across the width of the path 4. Alternatively, a mobile feedstock applicator 15 may include a single outlet 33 which extends in the second direction, y so as to span the width of the path 4.

A flexible feedstock supply line 35 may connect the mobile feedstock applicator 15 to a 10 supply of carbon containing feedstock as the mobile feedstock applicator 15 moves along the path 4.

Referring also to Figures 11 and 12, a feedstock application system 6 including a number of static feedstock outlets 17 is shown.

The static feedstock outlets 17 are spaced along the path 4. Each static feedstock outlet is directed towards the growth substrate 3 and is configured to apply carbon containing feedstock to a corresponding application area 7 of the growth substrate 3 when the static feedstock outlet 17 is actuated. The static feedstock outlets 17 may be 20 configured for independent actuation, or groups of static feedstock outlets 17 may be configured to be actuated as a group. The actuation of static feedstock outlets 17 may be provided by corresponding electromechanical valves (not shown). The static feedstock outlets 17 are each connected to a pipe or conduit 36 which supplies the carbon containing feedstock.

The static feedstock outlets 17 are configured to be actuated according to a sequence, such that an active application area 7 is controllably moveable along the path 4. For example, as shown in Figure 11 a group of static feedstock outlets 17* are open to discharge liquid or gaseous carbon containing feedstock across the application area 7, 30 whilst the other static feedstock outlets 17 remain closed and do not discharge carbon containing feedstock.

The actuation of the static feedstock outlets 17 is coordinated with the motion of the heated area 10. For example, the active application area 7 may move a short distance 35 ahead of the heated area 10. Alternatively, the active application area 7 may overlap or

-25coincide with the heated area to. The latter option maybe advantageous when the carbon containing feedstock is a gas.

The static feedstock outlets 17 may be arranged to either side of the growth substrate 3 as shown in the example of Figure 12. However, especially when the growth substrate 3 is wide in the second direction y, it may be preferable to employ static feedstock outlets 17 positioned above the growth substrate 3. In some examples, static feedstock outlets may be provided beneath the graphene growth substrate 3. For example, the static feedstock outlets 17 may dispense carbon containing feedstock into or through a growth substrate 3 which has been melted by the heating system 9.

The arrangement of static feedstock outlets 17 may be combined with a linear guideway system 16. For example, an apparatus 1 may use a feedstock application system 6 which include a mobile feedstock applicator 15 in addition to static feedstock outlets 17.

The flexibility of configuring the feedstock application system 6 may be advantageous in ensuring substantially complete and uniform application of the carbon containing feedstock.

Arrangements of static feedstock outlets 17 may typically by used to dispense gaseous or liquid carbon containing feedstock. However, with appropriate adaptations, static feedstock outlets 17 may also be used to dispense solid feedstocks in the form of powders.

Heating system

Referring also to Figure 13, the heating system 9 may include a mobile heating element mounted to a linear guideway 16.

The linear guideway 16 may take the form of one or more rails or other suitable guiding structures which follow the path 4 defined by the growth substrate 3. The linear guideway 16 is enclosed within the reactor vessel 2. The linear guideway 16 may take the form of one or more rails disposed above and/or to either side of the growth substrate 3.

Movement of the mobile heating element 18 in the direction 8 along the path 4 maybe 35 provided by mechanisms integrated with the mobile heating element 18 and engaged with the linear guideway. Alternatively, the mobile heating element 18 may be

- 26 connected to a cord or chain which is supported within or adjacent to the linear guideway 16 and free to move with respect to the linear guideway 16. Examples of mechanisms for propelling the mobile heating element 18 include, but are not limited to, re-circulating rolling elements located between the linear guideway 16 and a bearing 5 block forming part of the mobile heating element 18, as well as linear synchronous motors and, for high speeds, a linear induction motor.

The mobile heating element 18 may heat a feedstock layer 34 on the growth substrate 3 surface 27 and the carbon containing feedstock is decomposed, with or without catalysis by the growth substrate, to release carbon, hydrogen and so forth. The released carbon forms a layer 11 of graphene and/or carbon nanostructures on the growth substrate 3. In some examples, for instance where the carbon containing feedstock is a gas which does not substantially adsorb onto the surface 27, there need not be a feedstock layer 34 and instead gaseous carbon containing feedstock which comes into contact with the heated area 10 of the growth substrate 3 may be decomposed to release carbon for forming the layer 11 of graphene and/or carbon nanostructures. Outlets (not shown) in the reactor vessel 2 allow liberated hydrogen and other gases from the decomposed carbon containing feedstock to be released.

The mobile heating element 18 may employ any suitable heating mechanism such as, for example, lasers, optical flash lamps, microwave sources, electromagnetic induction heating, resistive Joule heating and so forth. Examples of suitable mobile heating elements 18 which may be readily adapted for the apparatus 1 include, for example, laser welding systems, induction based welding systems, flame welding systems, heating systems used in zone-refining, and so forth, any of which may be readily adapted to moderate the amount of heat supplied. A mobile heating element 18 in the form of a laser or microwave source maybe tuned to selectively heat the growth substrate 3 and/or a feedstock layer 34. Induction heating of a metallic growth substrate 3 is inherently selective since eddy currents will not be generated in a support 30 layer 5 formed of, for example, quartz or fused silica.

Depending on the type of mobile heating element 18 used, the heated area 10 may span the width of the growth substrate 3 in the second direction y. Alternatively, the heated area 10 may be smaller than the width of the growth substrate 3 in the second direction 35 y, and the heated area 10 may be scanned or rastered in the second direction 7 at a

-27relatively faster speed than the mobile heating element 18 moves along the path 4 in the first direction x.

The mobile heating element 18 may operate in ambient pressures or under conditions of vacuum or ultra-high vacuum processing. As described hereinbefore, the mobile heating element 18 may heat the heated area 10 to a temperature between 15 °C and 2000 °C. Depending on the material forming the growth substrate 3, local melting within the heated area 10 may occur. Melting of the growth substrate 3 may be intentional and may be a part of the growth mechanism of a layer 11 of graphene and/or 10 carbon nanostructures. For example, by segregation of carbon dissolved in the melted growth substrate 3 upon solidification, or by molten salt synthesis mechanisms. In other examples, melting of the growth substrate 3 may be incidental and may have no bearing on the mechanism of forming a layer 11 of graphene and/or carbon nanostructures.

The mobile heating element 18 may be mounted to the same linear guideway 16 as a mobile feedstock applicator 15. The mobile heating element 18 and associated heated area 10 may arrive at a point of the growth substrate 3 at a time interval between milliseconds and seconds following the passage of the application area 7. Alternatively, 20 the heated area 10 may overlap with or substantially coincide with the application area.

For example, the mobile heating element 18 maybe a laser based system directed at a point on the path 4 which is ahead of the mobile heating element 18 and coincident with the application area 7. Alternatively, a mobile heating element 18 may be combined with number of static feedstock outlets 17 and the timing of the mobile heating element 18 and actuation of the static feedstock outlets 17 may be coordinated so that the active application area 7 overlaps or coincides with the heated area 10.

By heating the growth substrate 3 only in the region where carbon containing feedstock has been introduced, the energy efficiency of producing a layer 11 of graphene and/or 30 carbon nanostructures may be improved.

Referring also to Figure 14, the heating system 9 may additionally or alternatively include a number of static heating elements 19 spaced along the path 4.

Each static heating element 19 is arranged to heat a corresponding heated area 10 of the growth substrate 3. Each static heating element 19 maybe of any type described

- 28 hereinbefore in relation to mobile heating elements 18 such as, for example, lasers, microwave sources, induction heaters, resistive heaters, flames or torches and so forth.

The static heating elements 19 are configured to be actuated according to a sequence such that an active heated area 10 is controllably moveable along the path 4. Each static heating element 19 maybe configured for independent actuation. For example, each static heating element 19 may be switched on using a switch 37. The switches 37* for active static heating elements ^corresponding to the active heated area 10 are closed, whilst the other switches 37 remain open. Alternatively, the static heating elements 19 may be configured to be actuated in groups of two or more.

The static heating elements 19 maybe positioned above, below or to either side of the growth substrate 3.

Static heating elements 19 are static with respect to the path 4. Some static heating elements 19 may extend across the width of the growth substrate 3 in the second y direction. Other static heating elements 19 may correspond to a heated area 10 which is smaller than the width of the growth substrate 3 in the second y direction. Such static heating elements 19 may scan or raster the heated area 10 across the width of the growth substrate 3 in the second y direction and/or for a finite distance along the path 4·

Referring also to Figure 15, a heating system 9 in the form of coils 38 embedded below the support layer 5 is shown.

The coils 38 maybe embedded in a coil supporting layer 39 bonded directly to the support layer 5. Depending on the coil 38 properties, they may be used for resistive heating or for induction heating. For example, if the coils 38 are designed with a high resistance R, they may heat the overlying support layer 5 and growth substrate 3 by 30 resistive Joule heating I²R when current I is supplied to active coils 38* defining the heated area 10. Alternatively, the coils 38 may be configured for low resistance, in order to allow application of large, alternating currents I so as to cause induction heating by generating eddy currents in an overlying conductive (e.g. metallic) growth substrate 3. Induction heating may be preferred in some examples because it is both 35 rapid and selective to conductive objects, which may further improve the energy efficiency of producing a layer 11 of graphene and/or carbon nanostructures.

-29Referring also to Figure 16, a heating system 9 may include a radiation source 40 and a number of actuatable reflection elements 41 spaced along the path 4.

The growth substrate 3 defines a straight, linear path 4, and the radiation source 40 is arranged to emit one or more beams of radiation energy 42 parallel to the path 4. The radiation source 40 may take the form or one or more visible or infra-red lasers, one or more microwave sources, one or more microwave lasers and so forth. The radiation source 40 may be tuned to an absorbance of the growth substrate 3 or an absorbance of 10 the carbon containing feedstock. Although most growth substrates 3 maybe metallic and will largely reflect microwave wavelength radiation, a layer 34 of carbon containing feedstock adsorbed, wetted or arranged over the surface 27 of the growth substrate 3 may interact strongly with microwave radiation of appropriate wavelength. Equally, gaseous carbon containing feedstock adsorbed on the surface 27 or simply present in 15 the volume corresponding to the heated area 10 may be strongly heated by microwave radiation of appropriate wavelength.

Although redirection of radiation energy 42 has been shown from above the growth substrate 3 in Figure 16, in other examples the radiation source 40 and reflection 20 elements 41 may be disposed below the support layer 5. For example, the radiation source 40 may be tuned to emit radiation 42 corresponding to an absorbance of the support layer 5 to heat the support layer 5 and overlying growth substrate 3, or the radiation source 40may be tuned to a transmission window of the support layer 5 to directly heat the growth substrate 3. In still further examples, the radiation source 40 25 and reflection elements 41 may be disposed to either side of the support layer 5.

The actuatable reflection elements 41 maybe mounted to a support plate 43 which may also include mechanisms (not shown) for controllably actuating the reflection elements 41. At a point along the path 4 corresponding to the desired heated area, a reflection 30 element 41* is actuated to an angle Θ so as to intersect and redirect the radiation energy 42 towards a corresponding heated area 10 of the growth substrate 3. The angle Θ may be fixed or, in some examples, the angle Θ may be scanned through a range so as to redirect the radiation energy along a portion of the path 4. The reflection elements 41 are configured to be actuated according to a sequence such that an active heated area 10 35 is controllably moveable along the path 4.

-30The reflection elements 41 may take the form of mirrors such as, for example, ultrafast mirrors known for use in femtosecond laser systems. Alternatively, when the radiation source 41 emits microwave radiation, the reflection elements 41 may take the form of flat, metallic foils. Preferably the reflection elements 41 are as light as possible to minimise actuation times.

Referring also to Figure 17, a heating system 9 may include a radiation source 40 and a mobile reflection element 44 which is controllably moveable along the path 4.

The growth substrate 3 defines a straight, linear path 4, and the radiation source 40 is arranged to emit one or more beams of radiation energy 42 parallel to the path 4. The radiation source 40 may be of any type described hereinbefore.

The mobile reflection element 44 is mounted on a carriage 45 which is mounted to a linear guideway 16 and configured to displace the mobile reflection element 44 in the direction 8 along the path. As the mobile reflection element 44 is moved along the path 4, the corresponding heated area 10 into which the radiation energy 42 is reflected moves with the carriage 45 and mobile reflection element 44. The mobile reflection element 44 may be a mirror or, when the radiation energy 42 is of microwave wavelengths, the mobile reflection element 44 may simply be a flat metallic plate.

The reflection elements 41, 44 need not be planar. In some examples the reflection elements may be concave or convex to respectively focus or defocus a beam of radiation energy 42.

For example, referring also to Figure 18, concave reflection elements 46 maybe used.

Parallel radiation energy 42 incident on an actuated concave reflection element 46* may be focused to a heated area 10 in the form of a spot 47 on the surface of the growth substrate 3. The heated area 10 may be scanned along the path 4 by varying the angle Θ of the actuated concave reflection element 46* until eventually the next concave reflection element 46 along the path takes over.

Alternatively, referring also to Figure 19, convex reflection elements 48 may be used.

-31Parallel radiation energy 42 incident on an actuated convex reflection element 48* may be defocused to spread the incident radiation energy 42 evenly across the desired heated area 10 of the growth substrate 3.

Mobile reflection elements 44 may also be concave or convex.

Referring also to Figure 20, an example of forming a layer 11 of graphene and/or carbon nanostructures is illustrated.

A feedstock layer 34 comprising adsorbed gaseous carbon containing feedstock, or a layer of carbon containing feedstock in solid, liquid, paste or ink forms, is present on the surface 27 of the growth substrate 3 following passage of the application area 7. A mobile reflection element 44 in the form of a metal plate redirects radiation energy 42 at microwave wavelengths onto the feedstock layer 34. Within the heated area 10, the carbon containing feedstock is heated to form a reaction mass 49 as the carbon containing feedstock breaks down to release carbon, and also hydrogen and/or other gasses 50. As the heated area 10 moves on, a layer 11 of graphene and/or carbon nanostructures is left behind on the surface 27 of the growth substrate 3.

Referring also to Figure 21, a configurable waveguide system 51 for guiding microwave radiation 52 to a desired heated area 10 is shown.

Forming a beam of microwave radiation 52 may be difficult in practice and requires uninterrupted line of sight. Instead, a configurable waveguide system 51 maybe used 25 to guide microwave radiation 52 parallel to the path 4 until it is redirected toward the growth substrate 3.

The configurable waveguide system 51 includes a static plate 53 which is spaced apart from a number of actuatable waveguide elements 54. In a default configuration, the 30 actuatable waveguide elements 54 form a plate-like surface which, opposite the static plate 53 defines a microwave waveguide. Depending on the spacing, the configurable waveguide system 51 maybe single or multi-mode. At the location of the heated area 10, a waveguide element 54* is actuated about a hinge point 55 to redirect microwave radiation 52 out of the configurable waveguide system 51 and towards the growth substrate 3. By sequentially actuating the waveguide elements 54, an active heated area

-32may be moved along the path 4. The waveguide elements 54 may each extend across the entire width of the growth substrate 3 in the second direction y.

When not actuated, the actuatable waveguide elements 54 preferably interlock to an extent, in order to provide a plate surface which is as flat and continuous as possible.

Discontinuities between adjacent actuatable waveguide elements 54 providing a waveguide surface are acceptable so long as they remain substantially smaller than the wavelength of the micro wave radiation 52. Using micro wave radiation 52 with wavelengths in the range from several mm to tens of cm, it should be readily possible to 10 engineer adjacent actuatable waveguide elements 54 having sufficiency small discontinuities.

A configurable waveguide system 51 may be provided above and/or below the growth substrate 3.

An advantage of a configurable waveguide system 51 is that the path 4 need not be straight and linear, and may also include curves or corners.

Cooling system

Referring also to Figure 22, the cooling system 12 may include a mobile cooling element 20 mounted to a linear guideway 16.

The mobile cooling element 20 may include a nozzle or outlet 56 which dispenses cooling gas supplied by a flexible cooling gas supply line 57. The cooling gas is directed 25 towards the cooled area 13 of the growth substrate 3

The linear guideway 16 is the same as described hereinbefore, and parts of a feedstock application system 6 and/or a heating system 9 may be mounted to the same linear guideway 16 as the mobile cooling element 20.

The cooling gas maybe at ambient temperature, which maybe substantially below a temperature of the heated area 10. Alternatively cooling gas may be cooled, for example to cryogenic temperatures. Any inert gas may provide the cooling gas such as, for example, argon or nitrogen. Additional gases may be adding to the cooling gas, for 35 example hydrogen, boron or nitrogen for doping layers 11 of graphene and/or carbon nanostructures.

-33The cooling system 12 may serve to rapidly cool a deposited layer 11 of graphene and/or carbon nanostructures left behind the heated area 10, for example, when formation of the layer 11 of graphene and/or carbon nanostructures is by a surface catalysis mechanism. In such examples, the cooling system 12 may cause rapid cooling such that thermal mismatch strains between the layer 11 of graphene and/or carbon nanostructures and the growth substrate 3 may assist in de-laminating the layer 11 of graphene and/or carbon nanostructures. Alternatively, thermal mismatch strains may weaken the adhesion between the layer 11 of graphene and/or carbon nanostructures and the growth substrate 3 prior to a subsequent peeling operation.

Alternatively, when the layer 11 of graphene and/or carbon nanostructures is formed by precipitation or segregation of carbon from the bulk of the growth substrate 3, or upon solidification of a molten growth substrate 3, the cooling system 12 maybe an integral 15 part of the formation mechanism of the layer 11 of graphene and/or carbon nanostructures.

The cooling system 12 may be configured to control a cooling rate of the growth substrate 3 so as to control the thickness and/or morphology of a layer 11 of graphene 20 and/or carbon nanostructures formed on the surface 27 of the growth substrate 3. For example, the cooling system 12 may be configured to control whether monolayer or multi-layer graphene is produced. The cooling system may be configured to cool the cooled area to a given temperature within a range from 15 °C to 1000 °C. A specific target cooling temperature generally depends on the material forming the growth 25 substrate 3.

As described hereinbefore, the cooling system 12 is optional and may not be needed in some examples of the apparatus 1. In particular, the localised heating by the heating system 9 and the low thermal mass of the thin support layer 5 and growth substrate 3 30 corresponding to the heated area 10 will lead to naturally rapid cooling rates even without application of cooling gases.

Referring also to Figures 23 and 24, the cooling system 12 may additionally or alternatively include a plurality of static cooling elements 21 spaced along the path 4.

-34The static cooling elements 21 are spaced along the path 4 and may take the form of actuatable nozzles or outlets for cooling gas. Each static cooling element 21 is directed towards the growth substrate 3 and is configured to apply cooling gas to a corresponding cooled area 13 of the growth substrate 3 when the static cooling element 5 21 is actuated. The static cooling elements 2imay be configured for independent actuation, or groups of static cooling elements 2imay be configured to be actuated as a group. The actuation of static cooling elements 2imay be provided by corresponding electromechanical valves. The static cooling elements 21 are connected by a pipe or conduit 58 which supplies the cooling gas.

The static cooling elements 21 are configured to be actuated according to a sequence, such that an active cooled area 13 is controllably moveable along the path 4. For example, as shown in Figure 23 a group of static cooling elements 21* are open to discharge cooling gas across the cooled area 13 whilst the other static cooling elements 15 21 remain closed and do not discharge cooling gas.

The actuation of the static cooling elements 21 is coordinated with the motion of the heated area 10. For example, the active cooled area 13 may move a short distance behind of the heated area 10.

The static cooling elements 21 may be arranged to either side of the growth substrate 3 as shown in the example of Figure 24. However, especially when the growth substrate 3 is wide in the second direction y, it may be preferable to employ static cooling elements 21 positioned above the growth substrate. In some examples, static cooling elements 21 25 may be provided beneath the growth substrate 3.

Examples

Referring also to Figure 25 a portion of a first example apparatus 59 is shown.

The first example apparatus 59 includes a mobile feedstock applicator 15, a mobile heating element 18 and a mobile cooling element 20 as described hereinbefore. The mobile feedstock applicator 15, mobile heating element 18 and mobile cooling element 20 are all mounted to the same linear guideway 16 and progress along the path 4 in the direction 8 in a train-like manner.

-35In this way, a fixed location on the surface 27 of the growth substrate 3 is first exposed to carbon containing feedstock as the application area 7 passes, followed by rapid heating to high temperatures as the heated area 10 passes to decompose the carbon containing feedstock. Once the cooled area 13 has passed the location, the surface 27 of 5 the growth substrate 3 is left coated with a layer 11 of monolayer or multi-layer graphene and/or carbon nanostructures. The thickness, composition and morphology of the layer 11 depends on the combination of growth substrate 3 material, carbon containing feedstock material, heating temperature and duration, and the cooling rate.

In this way, the path 4 defined by the extension of the growth substrate 3 may be used for large scale batch production, or even continuous production of large area graphene layers 11 or large layers 11 of carbon nanostructures. For example, one way in which the apparatus 1 enables very long paths 4 is through the application of localised, movable application, heated and cooled areas 7,10,13. This may enable energy efficient processing since a large reactor vessel need not be filled with feedstock, heated and optionally cooled as a whole unit. At the same time, because the growth substrate 3 is stationary, a wider range of materials may be considered, for example in contrast to proposed roll-to-roll production methods which require using mechanically robust metal foils.

Another advantage of the present apparatus 1,59 is that production of large area graphene layers 11 or large layers 11 of carbon nanostructures is enabled for molten growth substrates 3. Only a local area of the growth substrate 3 needs to be melted at any time, leading to improved efficiency compared to melting the entire growth substrate 3 simultaneously. In this way, graphene and/or carbon nanostructure production using molten growth substrates 3 may be scaled up to larger quantities.

The path 4 may be up to hundreds of metres long, and may form a closed loop. The path 4 may be up to tens of metres wide. Multiple paths 4 may be defined by growth substrates 3 arranged in parallel and/or vertically stacked, as described hereinafter. In this way, the apparatus 1 may permit scalable, large scale production of layers 11 of graphene and/or carbon nanostructures.

Referring also to Figure 26 a portion of a second example apparatus 60 is shown.

-36The second example apparatus 60 includes a mobile feedstock applicator 15, a mobile heating element 18 and a number of static cooling elements 21 spaced along the path 4, as described hereinbefore. The mobile feedstock applicator 15 and mobile heating element 18 are both mounted to the same linear guideway 16 and progress along the 5 path 4 in the direction 8 in a train-like manner. At the same time, the actuation of static cooling elements 21 is timed with the passage of the mobile feedstock applicator 15 and mobile heating element 18 such that static cooling elements 21* are actuated to release cooling gas at an interval of milliseconds or seconds following the passage of the heated area.

In this way, a fixed location on the surface 27 of the growth substrate 3 is first exposed to carbon containing feedstock as the application area 7 passes, followed by rapid heating to high temperatures as the heated area 10 passes to decompose the carbon containing feedstock. After the heated area 10 has passed, the adjacent static cooling elements 21* are actuated to release cooling gas, and the surface 27 of the growth substrate 3 is left coated with a layer 11 of graphene and/or carbon nanostructures. The thickness, composition and morphology of the layer 11 depends on the combination of growth substrate 3 material, carbon containing feedstock material, heating temperature and duration, and the cooling rate.

The second example apparatus 60 provides at least the same advantages as the first example apparatus 59.

Referring also to Figures 27 and 28 a portion of a third example apparatus 61 is shown.

The third example apparatus 61 includes a number of static feedstock outlets 17 spaced along the path 4, a mobile heating element 18, and a number of static cooling elements 21 spaced along the path 4, as described hereinbefore. The mobile heating element 18 is mounted to the linear guideway 16 and progress along the path 4 in the direction 8 as 30 described hereinbefore. At the same time, the actuation of static feedstock outlets 17 and static cooling elements 21 is timed with the passage of the mobile heating element

18. In this way, static feedstock outlets 17* are actuated as the mobile heating element 18 passes so that the application area 7 and heated area 10 overlap at least partially.

This may be advantageous for gaseous carbon containing feedstock, because the feedstock may be concurrently applied and heated. Similarly, static cooling elements

-3721* are actuated to release cooling gas at an interval of milliseconds or seconds following the passage of the heated area 10.

In this way, a fixed location on the surface 27 of the growth substrate 3 is exposed to carbon containing feedstock as the adjacent static feedstock outlets 17* are actuated, whilst being concurrently heated to high temperatures to decompose the carbon containing feedstock. After the heated area 10 has passed, the adjacent static cooling elements 21* are actuated to release cooling gas, and the surface 27 of the growth substrate 3 is left coated with a layer 11 of graphene and/or carbon nanostructures. The 10 thickness, composition and morphology of the layer 11 depends on the combination of growth substrate 3 material, carbon containing feedstock material, heating temperature and duration, and the cooling rate.

The third example apparatus 61 also provides at least the same advantages as the first 15 example apparatus 59.

In the example shown in Figures 27 and 28, the static feedstock outlets 17 and static cooling elements 21 are provided from pipes or conduits 36, 38 on either side of the growth substrate 3. The mobile heating element 18 is suspended by a carriage 62 and 20 wheels or rollers 63 from a rail 64.

However, in a modified third example apparatus (not shown), the static feedstock outlets 17 and static cooling elements 21 may be provided over the growth substrate 3 whilst the linear guideway 16 is provided by a pair of rails disposed either side of the 25 growth substrate 3.

Referring also to Figures 29 and 30 a portion of a fourth example apparatus 65 is shown.

The fourth example apparatus 65 includes a number of static feedstock outlets 17 spaced along the path 4, a number of actuatable reflection elements 41 spaced along the path 4, and a number of static cooling elements 21 spaced along the path 4, as described hereinbefore. The pipes or conduits 36, 58 respectively supplying carbon containing feedstock and cooling gas may by contained within a pair of support structures 66 arranged on either side of the growth substrate 3. The actuations of static feedstock outlets 17, actuatable reflection elements 41 and static cooling elements 21 are

-38timed such that a given location on the surface 27 of the growth substrate 3 is first exposed to carbon containing feedstock, then irradiated by the redirected radiation 42, and finally cooled by cooling gas. In this way, the application area 7, heated area 10 and cooled area 13 may be moved along the path in a sequence.

In an alternative method of using the fourth example apparatus 65, the static feedstock outlets 17* may be actuated at the same time as overhead reflection elements 41, so that the application area 7 and heated area 10 overlap at least partially. This may be advantageous for gaseous carbon containing feedstock, because the feedstock may be concurrently applied and heated.

Concave reflection elements 46 or convex reflection elements 48 may alternatively be used in the fourth example of the apparatus 65.

The fourth example apparatus 65 provides at least the same advantages as the first example apparatus 59.

Referring also to Figures 31 and 32 a portion of a fifth example apparatus 67 is shown.

The fifth example apparatus 67 includes a mobile feedstock applicator 15, a number of actuatable reflection elements 41 spaced along the path 4, and a mobile cooling element 20, as described hereinbefore. The mobile feedstock applicator 15 and the mobile cooling element 20 are both mounted to the same linear guideway 16 and progress along the path 4 in the direction 8 in a train-like manner. The linear guideway 16 in this example includes a pair of rails 64 positioned to either side of the growth substrate

3. The mobile feedstock applicator 15 and the mobile cooling element 20 both span the width of the growth substrate 3 in the second direction y, and are mounted to the rails 64 using rollers or wheels 63.

After the mobile feedstock applicator 15 has passed a point on the surface 27 of the growth substrate 3, and before the arrival of the mobile cooling element 20, an actuatable reflection element 41 corresponding to that point of the surface 27 is actuated to redirect radiation 42 towards the growth substrate 3. Subsequently, the mobile cooling element 20 passes to cool and/or precipitate the layer 11 of graphene and/or carbon nanostructures. The timing of actuating the reflection elements 41 is controlled so that the actuated reflection element 41* always lies between the mobile

-39feedstock applicator 15 and the mobile cooling element 20. The actuated reflection element 41* may be moved to an angle which is time varying, so that a heated area 10 is scanned along the path 4 at the same speed as the application area 7 and cooled area 13.

Concave reflection elements 46 or convex reflection elements 48 may alternatively be used in the fifth example of the apparatus 67.

The fifth example apparatus 67 provides at least the same advantages as the first example apparatus 59.

Referring also to Figures 33 and 34 a portion of a sixth example apparatus 68 is shown.

The sixth example apparatus includes a number of static feedstock outlets 17 spaced along the path 4, a number of actuatable reflection elements 41 spaced along the path 4, 15 and a number of static cooling elements 21 spaced along the path 4, as described hereinbefore. The pipes or conduits 36, 58 respectively supplying carbon containing feedstock and cooling gas are contained within the support plate 43 to which the actuatable reflection elements 41 are mounted. The actuations of static feedstock outlets 17, actuatable reflection elements 41 and static cooling elements 21 are timed 20 such that a given location on the surface 27 of the growth substrate 3 is first exposed to carbon containing feedstock, then irradiated by the redirected radiation 42, and finally cooled by cooling gas. In this way, the application area 7, heated area 10 and cooled area 13 may be moved along the path in a sequence.

The difference between the sixth apparatus 68 and the fourth apparatus 65 lies principally in the relative arrangement of the static feedstock outlets 17 and static cooling elements 21. In the fourth apparatus 65 the static feedstock outlets 17 and static cooling elements 21 are disposed to either side of the growth substrate 3. By contrast, in the sixth apparatus 68, the static feedstock outlets 17 and static cooling 30 elements 21 are disposed above the growth substrate 3 along with the actuatable reflection elements 41.

In the sixth apparatus 68, the static feedstock outlets 17 and static cooling elements 21 are arranged in an alternating pattern, and each is arranged within a corresponding 35 aperture of the actuatable reflection elements 41. The static feedstock outlets 17 and static cooling elements 21 should not extend beyond a corresponding actuatable

-40reflection element 41 when that reflection element 41 is not actuated and parallel to the support plate 43.

In an alternative method of using the sixth example apparatus 68, the static feedstock outlets 17* may be actuated at the same time as overhead reflection elements 41*, so that the application area 7 and heated area 10 overlap at least partially. This may be advantageous for gaseous carbon containing feedstock, because the feedstock may be concurrently applied and heated.

Concave reflection elements 46 or convex reflection elements 48 may alternatively be used in the sixth example of the apparatus 68.

The sixth example apparatus 68 provides at least the same advantages as the first example apparatus 59.

Collection system

As described hereinbefore, the apparatus 1,59, 60, 61, 65, 67, 68 may also include a collection system 14 enclosed within the reactor vessel and configured to remove a layer 11 of graphene and/or carbon nanostructures formed on the growth substrate 3.

For example, referring also to Figure 35, a collection system 14 maybe configured to directly peel the layer 11 of graphene and/or carbon nanostructures off the growth substrate 3.

The collection system 14 is preferably configured to peel the layer 11 of graphene and/or carbon nanostructures off the growth substrate 3 without using any supporting substrate. Direct peeling may be preferred when multi-layer graphene is produced for application as, for example, fibre or sheet materials.

The collection system 14 may include a number of lift-off rollers 69 arranged to mechanically support the layer 11 of graphene and/or carbon nanostructures as it is peeled off the growth substrate 3. The collection system 14 should not remove the growth substrate 3 from the support layer 5. In this way, the growth substrate 3 remains attached to the support layer 5 and may be re-used for depositing further layers 11 of graphene and/or carbon nanostructures. The collection system 14 may

-41include a blade 70 to assist in mechanically cleaving or scraping the layer 11 of graphene and/or carbon nanostructures from the growth substrate 3.

In some examples (not shown), the growth substrate 3 may still be molten when the collection system 14 passes, and the collection system 14 may skim the layer 11 of graphene and/or carbon nanostructures from the molten surface of the growth substrate 3.

Alternatively, referring to Figure 36, a second collection system 71 may comprise an exfoliation roller 72 configured to exfoliate a layer 11 of graphene and/or carbon nanostructures from the growth substrate 3 using an adhesive substrate 73.

The adhesive substrate 73 may take the form of, for example, a polymeric substrate coated with a thermally releasable adhesive. The adhesive substrate 73 may be provided from drum or supply roller (not shown), and is pressed against a surface 74 of the layer 11 of graphene and/or carbon nanostructures by the exfoliation roller 72 to bond the adhesive substrate 73 to the layer 11 of graphene and/or carbon nanostructures. The adhesive substrate 73 is pulled away from the growth substrate 3 and in the process exfoliates the layer 11 of graphene and/or carbon nanostructures. A further re-directing roller or rollers 75 may re-direct the bonded adhesive substrate 73 and layer 11 of graphene and/or carbon nanostructures towards a take-up roller (not shown) which stores the produced and exfoliated layer 11 of graphene and/or carbon nanostructures.

The collection system 14, 71 may additionally include a transfer system 76 configured to transfer the layer to a capture plate 22 (Figure 37).

For example, referring also to Figure 37 and 38, in one example the transfer system 76 may include a transfer roller 77 which is rotated about an axis 78 which makes an angle

Φ with a perpendicular to the path 4, in a plane parallel to the surface 27 of the growth substrate 3. In other words, axis 78 makes an angle Φ with the second direction y. The transfer system 76 follows a peeling based collection system 14 and mechanically supports and rotates the peeled or skimmed layer 11 of graphene and/or carbon nanostructures onto the capture plate 22. The layer 11 of graphene and/or carbon nanostructures follows a portion of a helical path around the transfer roller 77.

-42The transfer system 76 may follow an exfoliation based collection system 71 and rotate the adhesive substrate 73 and layer 11 of graphene and/or carbon nanostructures to the capture plate 22 in the same way. Alternatively, the transfer roller 77 may also provide the exfoliation roller 72.

Extracting layers of graphene and/or carbon nanostructures from the reactor vessel In some examples, the apparatus 1,59, 60, 61, 65, 67, 68 maybe used for large scale batch production of layers 11 of graphene and/or carbon nanostructures.

However, it may be advantageous to extract produced layers 11 of graphene and/or carbon nanostructures without the need to cycle the reactor vessel 2 between normal atmosphere and process conditions.

Referring also to Figures 39 and 40, a wall of the reactor vessel 2 may include a rotating 15 load lock mechanism 79.

The rotating load lock mechanism 79 rotates a capture plate 22 bearing a layer 11 of graphene and/or carbon nanostructures to the exterior of the reactor vessel 2. The rotating load lock mechanism 79 maybe configured to prevent atmospheric gasses, and 20 in particular oxygen, from entering the reactor vessel 2 in significant quantities. For example, methods and systems for exchanging materials between controlled and uncontrolled environments may be adapted from the area of semiconductor chip processing.

Alternatively, instead of a rotating load lock, a capture plate 22 may be linearly displaced (not shown) outside the reactor vessel 2 via a two-door airlock mechanism (not shown). This can also provide excellent integrity for the reactor vessel 2 whilst allowing a capture plate 22 to be extracted without shutting down the entire apparatus 1,59, 60, 61, 65, 67, 68.

In a still further alternative, a growth substrate 3 and support layer 5 bearing a layer 11 of graphene and/or carbon nanostructures maybe rotated through a rotating load lock mechanism 79 or linearly displaced via a two-door airlock mechanism (not shown).

-43Examples of the path

Referring also to Figures 41 and 42, the growth substrate 3 may define a path 4 in the form of a closed loop.

Referring in particular to Figure 41, the growth substrate 3 may define a closed loop path 4 in the form of circle.

Referring in particular Figure 42, the growth substrate 3 may define a closed loop path 4 having a serpentine shape in which a number of straight sections 80 of the growth 10 substrate 3 are connected together by curved portions 81 of the growth substrate 3.

Referring also to Figure 43, the apparatus 1,59, 60, 61, 65, 67, 68 may also include, enclosed or received within the reactor vessel 2, one or more additional growth substrates 32,..., 36 supported on corresponding additional support layers 52,..., 56·

Each additional growth substrate 32,..., 3β may extend to define a corresponding additional path 42,..., 46. Each of the additional growth substrates 32,..., 36 is parallel to the growth substrate 3.

The feedstock application system 6 and the heating system 9 may be configured such that the application area 7 and the heated area 10 are each controllably moveable along a trajectory 82 which tracks the path 4 and also each additional path 42,..., 46.

When present, the cooling system 12 and the collection system 14, 71 may be similarly 25 controllably moveable along the trajectory 82.

In this way, multiple layers 11 of graphene and/or carbon nanostructures maybe deposited on multiple growth substrates 3,32,..., 36, which may help to enable scaling production quantities.

Furthermore, a layer 11 of graphene and/or carbon nanostructures peeled, skimmed or exfoliated from the growth substrate 3 and transferred to an adjacent capture plate 22 maybe extracted from the reactor vessel 2 (as described hereinbefore) whilst the feedstock application system 6 and heating system 9 form a layer 11 of graphene and/or 35 carbon nanostructures on the next growth substrate 32, and so forth. In this way, layers of graphene and/or carbon nanostructures maybe continuously produced in, then extracted from, the reactor vessel 2.

Alternatively, referring also to Figure 44, the apparatus 1, 59, 60, 61, 65, 67, 68 may include a separate feedstock application system 6 and a separate heating system 9 corresponding to the path 4 and to each additional path 42,..., 46.

When present, separate cooling systems and collection systems 14, 71 may be provided corresponding to each additional path 42,..., 46.

When a layer 11 of graphene and/or carbon nanostructures has been transferred from one of the growth substrates 3,32,..., 36 to a corresponding capture plate 22, the capture plate 22 may then be extracted from the reactor vessel 2 (as described hereinbefore). The processing of each growth substrate 3, 32,..., 36 maybe synchronised or staggered as compared to its neighbours.

Although Figures 43 and 44 have been illustrated using 6 growth substrates 3, 32,..., 36 in total, the number of parallel growth substrates 3,32,..., 36 is not limited to six, and many more additional growth substrates may be enclosed in the reactor vessel 2.

Modifications

It will be appreciated that many modifications may be made to the embodiments hereinbefore described. Such modifications may involve equivalent and other features which are already known in the design, manufacture and use of reactors for producing 25 graphene and/or carbon nanostructures, and which may be used instead of or in addition to features already described herein. Features of one embodiment may be replaced or supplemented by features of another embodiment.

Referring also to Figure 45, a modified collection system 83 additionally includes one 30 or more lasers 84 configured to direct a laser beam 85 at a layer 11 of graphene and/or carbon nanostructures to introduce corresponding discontinuities into the layer 11 of graphene and/or carbon nanostructures. This may assist in removal of the layer 11 of graphene and/or carbon nanostructures from the growth substrate 3. The laser(s) 84 may be configured to scission the layer 11 of graphene and/or carbon nanostructures 35 into strips running parallel to the path 4.

-45Each laser 84 may be, for example a solid-state laser, a dye laser, a gas laser, a laser diode, an excimer laser and so forth. Each laser 84 may be a red or infrared laser diode.

Additional, parallel growth substrates 32,..., 36 have been shown in Figures 43 and 44.

However, additional parallel growth substrates 32,..., 36 are not limited to horizontally spaced arrangements. Additionally or alternatively, additional growth substrates 3,32, ..., 36 may also be stacked vertically.

For example, referring also to Figure 46, growth substrates 3, support layers 5 and apparatus, for example the first apparatus 59, may be vertically stacked. This may further improve the scalability of producing layers 11 of graphene and/or carbon nanostructures. Vertical stacking is not limited to the first apparatus 59, and any examples of the apparatus 1,59, 60, 61, 65, 67, 68 may be vertically stacked.

The feedstock application system 6 and the heating system 9 have been described as separate systems. However, in some examples of the apparatus 1 the feedstock application system 6 and the heating system 9 maybe combined into a single element. For example, a torch which combines and burns carbon containing fuel with an oxidant maybe configured to be supplied with a surplus of carbon containing fuel. In this way, 20 the excess, un-oxidised carbon containing fuel may be supplied to the growth substrate at substantially the flame temperature, providing heat and carbon containing feedstock in a single element.

Throughout the specification, reference has been made to first x, second y and third directions z. This coordinate system should be understood to have been defined with respect to the path 4, such that a first, x direction is at every point coincident with the tangent to the path 4 and the second direction y always lies in the plane defined by the surface 27 of the growth substrate 3.

The first to sixth examples 59, 60, 61, 65, 67, 68 are merely examples of the apparatus

1, and should not be considered an exhaustive set. All combinations of the individually described feedstock application systems 7, heating systems 9, cooling systems 12 and collection systems 14, 71 are encompassed by the scope of this specification, excepting any combinations which are evidently incompatible. All that is essential for the apparatus 1 are that it includes at least one feedstock application system 6 of any type

-46described hereinbefore and at least one heating system 9 of any type described hereinbefore.

When the support layer 5 includes a recessed channel 26,31, a metallic growth substrate 3 may be easily prepared as follows. Firstly, a metallic foil or powder of the appropriate material may be placed in the recessed channel 26, 31. Secondly, the heating system 9 may be passed back and forth along the path 4 to melt the metallic foil or powder and, upon solidification, a metallic growth substrate 3 will be adhered to the support layer 5 or metallic adhesion layer 24 as appropriate. The heating system 9 may be similarly passed back and forth along the path 4 to anneal a metallic growth substrate 3 in order to increase the size of individual grains.

A similar process may be performed using a salt-based growth substrate 3. For example, a powder of the salt or salts maybe placed in the recessed channel 26,31, and, the heating system 9 may be passed back and forth along the path 4 to melt the powdered salt(s). Upon solidification, a salt-based growth substrate 3 will be adhered to the support layer 5 or metallic adhesion layer 24 as appropriate.

Although claims have been formulated in this application to particular combinations of features, it should be understood that the scope of the disclosure of the present invention also includes any novel features or any novel combination of features disclosed herein either explicitly or implicitly or any generalization thereof, whether or not it relates to the same invention as presently claimed in any claim and whether or not it mitigates any or all of the same technical problems as does the present invention.

The applicant hereby gives notice that new claims may be formulated to such features and/or combinations of such features during the prosecution of the present application or of any further application derived therefrom.

Claims

Claims

1. Apparatus for producing graphene and/or carbon nanostructures, comprising a reactor vessel configured to receive:

5 a growth substrate for forming graphene and/or carbon nanostructures, the growth substrate extending to define a path; and a support layer supporting the growth substrate;

the reactor vessel enclosing:

a feedstock application system configured to apply a carbon containing io feedstock to an application area of the growth substrate, wherein the application area for the carbon containing feedstock is controllably moveable along the path; and a heating system configured to heat a heated area of the growth substrate, wherein the heated area is controllably moveable along the path.
2. Apparatus according to claim 1, wherein the growth substrate comprises a metallic film.
3. Apparatus according to claim 1, wherein the growth substrate comprises a salt, 20 an oxosalt, a metal halide or an ionic liquid.
4. Apparatus according to any one of claims 1 to 3, wherein the support layer is formed of a material having a higher melting point than the growth substrate.

25 5. Apparatus according to any one of claims 1 to 4, wherein the support layer comprises a recessed channel and the growth substrate is supported within the recessed channel.

6. Apparatus according to any one of claims 1 to 5, further comprising a metallic

30 adhesion layer provided between the support layer and the growth substrate.

7. Apparatus according to any one of claims 1 to 6, wherein the feedstock application system comprises a mobile feedstock applicator mounted to a linear guideway.

8. Apparatus according to any one of claims 1 to 7, wherein the feedstock application system comprises a plurality of static feedstock outlets spaced along the path, each static feedstock outlet configured to apply the carbon containing feedstock to a corresponding application area of the growth substrate when the static feedstock
5 outlet is actuated;

wherein the static feedstock outlets are configured to be actuated according to a sequence such that an active application area is controllably moveable along the path.
9. Apparatus according to any one of claims 1 to 8, wherein the heating system
10 comprises a mobile heating element mounted to a linear guideway.

10. Apparatus according to any one of claims 1 to 9, wherein the heating system comprises a plurality of static heating elements spaced along the path, each static heating element configured to heat a corresponding heated area of the growth

15 substrate;

wherein the static heating elements are configured to be actuated according to a sequence such that an active heated area is controllably moveable along the path.
11. Apparatus according to any one of claims 1 to 10, wherein the heating system

20 comprises:

a radiation emitting system configured to emit radiation energy; and at least one reflection element configured to redirect the radiation energy to heat a heated area of the growth substrate.

25
12. Apparatus according to claim 11, wherein the at least one reflection element comprises a mirror configured to be controllably moveable along the path.
13. Apparatus according to claim 11, wherein the at least one reflection element comprises a plurality of mirrors, each mirror configured to be actuated to cause the

30 mirror to redirect radiation energy to a corresponding heated area of the growth substrate;

wherein the plurality of mirrors are configured to be actuated according to a sequence such that an active heated area is controllably moveable along the path.

35
14. Apparatus according to any one of claims 1 to 13, further comprising:

-49a cooling system enclosed within the reactor vessel and configured to cool a cooled area of the growth substrate, the cooled area being controllably moveable along the path.

5
15. Apparatus according to claim 14, wherein the cooling system comprises a mobile cooling element mounted to a linear guideway.
16. Apparatus according to claims 14 or 15, wherein the cooling system comprises a plurality of static cooling elements spaced along the path, each static cooling element

10 configured to cool a corresponding cooled area of the growth substrate; wherein the static cooling elements are configured to be actuated according to a sequence such that an active cooled area is controllably moveable along the path.
17. Apparatus according to any one of claims 1 to 16, further comprising a collection 15 system enclosed within the reactor vessel and configured to remove a layer of graphene and/or carbon nanostructures formed on the growth substrate.
18. Apparatus according to claim 17, wherein the collection system is configured to transfer the layer of graphene and/or carbon nanostructures to a capture plate.
19. Apparatus according to claim 18, wherein the reactor vessel comprises a rotating load lock configured to rotate the capture plate to the exterior of the reactor vessel to permit extraction of the removed layer of graphene and/or carbon nanostructures.
20. Apparatus according to any one of claims 1 to 19, wherein the path defines a closed loop.
21. Apparatus according to any one of claims 1 to 20, wherein the reactor vessel

30 encloses the growth substrate and the support layer.
22. Apparatus according to any one of claims 1 to 20, wherein the reactor vessel is further configured to receive one or more additional growth substrates, each additional growth substrate being supported on a corresponding additional support layer, and

35 wherein each additional growth substrate extends to define a corresponding additional path.

-5023- Apparatus according to claim 21 further comprising one or more additional growth substrates, wherein each additional growth substrate is supported on a corresponding additional support layer, and wherein each additional growth substrate 5 extends to define a corresponding additional path.
24. Apparatus according to claim 22 or claim 23, further comprising a separate feedstock application system and a separate heating system corresponding to each additional path.
25. Apparatus according to claim 22 or claim 23, wherein the feedstock application system and the heating system are configured such that the application area and the heated area are each controllably moveable along the path and along each additional path.
26. A method of producing graphene and/or carbon nanostructures inside a reactor vessel which is configured to receive a growth substrate for forming graphene and/or carbon nanostructures and which extends to define a path, and a support layer supporting the growth substrate, the method comprising:

20 applying a carbon containing feedstock to an application area of the growth substrate;

heating a heated area of the growth substrate;

controlling the application area and the heated area to move along the path.