CN104882346B - Method for preparing field emission cathode of carbon nanotube array coated with carbon nanoparticles - Google Patents
Method for preparing field emission cathode of carbon nanotube array coated with carbon nanoparticles Download PDFInfo
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Abstract
The invention discloses a method for preparing a field emission cathode of a carbon nanotube array coated with carbon nanoparticles, and belongs to the fields of nano material preparation and application. The method mainly comprises the following preparation process of preparing a carbon nanotube array on a silicon single crystal wafer by a thermal chemical vapor deposition method; producing hydrogen plasmas by using the radio frequency technology and processing the carbon nanotube array for a long time at low power; and finally, taking the carbon nanotube array coated on the surface with carbon nanoparticles as a cathode assembly field electron emitter. According to the invention, the prepared carbon nanotube array coated with the carbon nanoparticles by the method has a general particle diameter of 15-30 nm, and as the field emission cathode material, the carbon nanotube array has a lower open field and threshold field than a single carbon nanotube array, better field emission stability, and a higher application value.
Description
Technical field
The present invention obtains state natural sciences fund youth fund funded projects (bullets 51302187).Obtain sky
Jinshi City's application foundation subsidizes (bullets 14jczdjc32100) with cutting edge technology research plan key project；The invention belongs to
Nano material preparation and application technical field, relates to the use of low-power plasma technique and prepares and a kind of have receiving of unique texture
Rice material, and it is used for the preparation method of field electronic emitter part.
Background technology
Develop the focus that high performance filed emission cathode material is always recent researches, these materials are in New-generation vacuum
Pipe, x-ray tube, Electronic Speculum electron gun, field emission flat show etc. that numerous areas all have a good application prospect.CNT
It is exactly a kind of ideal filed emission cathode material.First, CNT is mainly by sp2Hydbridized carbon atoms form, and have non-
Often good electric conductivity.Secondly, CNT also has the huge draw ratio that many one-dimensional, two-dimension nano materials hardly match, and makes
Obtain electronics and can obtain great local electric field intensity (i.e. field enhancement factor is larger) at its Flied emission point, so that it is more easy to
Overcome carbon nano tube surface potential barrier (escape work function) to escape in vacuum, this to obtain low unlatching field and threshold field and
Big Flied emission electric current density is all very favorable.Compare the graphene-based field-transmitting cathode material obtaining extensive concern in recent years
Material, the field-transmitting cathode with CNT as base has lower unlatching field, is typically less than 2 v/ μm, and the unlatching of Graphene
Field is then commonly greater than 4 v/ μm.The feature of this low unlatching field is very important in actual applications, can pole significantly
Reduce the running voltage of field-transmitting cathode.As can be seen here, further reduce the work electricity of carbon nanotube field emission cathode material
, obtain bigger Flied emission electric current density, its practical value will be lifted.But, CNT is due to its own geometric shape
Impact, field-electron emission occur mainly in radius of curvature less tip (more sharp), flat tube wall does not then almost have
There is field-electron emission, i.e. the effect of external electric field is merely able in the sufficiently large local electric field of the most advanced and sophisticated formation of CNT, and electronics is at this
Carbon nano tube surface potential barrier can be overcome to escape in the presence of planting big local electric field, but due to local electric field intensity on tube wall
Not, field electronics can not escape.CNT is this only to be reduced to a great extent in the feature of most advanced and sophisticated launching site electronics
The number of its effective field launch point, is unfavorable for the field-electron emission of high current density.If it is possible to by certain handss
Section makes CNT in addition to tip, and also more new effective field launch points are it is possible to reduce carbon to a certain extent
The unlatching field of nanotube and threshold field, and increase its Flied emission electric current density.
Field-transmitting cathode with CNT as base is one-dimensional due to it, and heat-delivery surface is relative to this two dimension of Graphene
Material is little, is affected be more susceptible to Joule heat in emission process on the scene, particularly in the case of high current density Flied emission,
A part of effective field launch point can burn because of a large amount of accumulation of Joule heat, and this will reduce cathode material to a certain extent
Field-electron emission ability, that is, compared to this two-dimension nano materials of Graphene, its field emission stability is poor for CNT, this
Significantly shortened the service life of CNT base field-transmitting cathode in actual applications.Research shows, at plasma
Reason CNT can effectively remove those rich defects, contact unstable CNT, and these CNTs exactly field is sent out
Be emitted through the principal element that journey midfield emission current declines, under action of plasma by removal undoubtedly will lift field-transmitting cathode
The field emission stability of material.Additionally, long-time the high temperature anneal also can reduce rich defect carbon nanometer to a certain extent
The quantity of pipe, so that the field-transmitting cathode with CNT as base has more preferable field emission stability.
As can be seen here, more effective field launch points are made it have by introducing technological means process CNT, to drop
Low its is opened field and threshold field, is lifted its Flied emission electric current density, and this technological means can also lift it to a certain extent
Field emission stability, the filed emission cathode material with CNT as base making prepared is had higher using value.
Content of the invention
It is an object of the invention to overcome the existing transmitting of the field-transmitting cathode effective field with CNT as base to count out less,
Open the deficiency that field and threshold field are of a relatively high, Flied emission electric current density is relatively low, field emission stability is bad, using a kind of letter
Single low-power plasma process processes carbon nano pipe array, provides and a kind of opens field and threshold field is low, Flied emission electric current is close
The CNT base filed emission cathode material that degree is big, field emission stability is good.
The purpose of the present invention is reached by following measure:
A kind of preparation method of the carbon nano-tube array field emission cathode of carbon nano-particle cladding is it is characterised in that using penetrating
Frequency technology produces hydrogen plasma to process the carbon nano pipe array of thermal chemical vapor deposition method preparation, adjusts radio-frequency power and is
30-50w, base reservoir temperature are 1000k, reative cell air pressure is 100pa, process time is 10-30 hour, finally obtain different-shape
Carbon nano-particle cladding carbon nano-tube array field emission cathode material；Described carbon nano-particle refers to diameter and is generally
The granule of 15-30 nanometer.
Carbon nano pipe array of the present invention can be prepared with traditional thermal chemical vapor deposition method it is also possible to other appoint
The method of the array carbon nano tube prepared of meaning is preparing.
The preparation method of the carbon nano-tube array field emission cathode of carbon nano-particle cladding of the present invention, uses in preparation
Can be lower powered radio frequency source or other arbitrarily can produce low power density in producing the device of hydrogen plasma
The device of hydrogen plasma.
The present invention further discloses the preparation method of the carbon nano-tube array field emission cathode of carbon nano-particle cladding, its
It is characterised by carrying out as follows:
(1) it is cleaned by ultrasonic each in deionized water, acetone and dehydrated alcohol successively for silicon single crystal flake 10 minutes, ultrasonic power
For 50w, its object is to remove the organic pollution of silicon wafer surface.
(2) silicon wafer obtaining step (1) is placed in the Fluohydric acid. that volume ratio is 4% and soaks 5 minutes, and its purpose exists
In the silica overlayer removing silicon wafer surface, naturally dry afterwards.
(3) silicon wafer that step (2) is obtained carry out in metal vapor vacuum arc source (mevva source) carry can ferrum from
Son bombardment pretreatment, during bombardment, iron ion energy is about 15kev, and line is 10 milliamperes, and process time is 15 minutes, and its purpose exists
Adhesion between lifting CNT and silicon base.
(4) silicon wafer bombarding the load energy iron ion that step (3) obtains inserts deposit thickness in magnetic control sputtering device
For 5 nanometers of iron catalyst, method particularly includes: silicon wafer is put on sample stage in magnetic control sputtering device, source of iron is a diameter
High-purity (4n) ferrum target for 75 millimeters, is first evacuated to about 8 × 10-5Pa, then passes to high-purity (5n) argon, adjusts deposition chambers
Air pressure is 1.0pa, and during deposition, DC source electric current is 60 milliamperes, adds 150 volts of back bias voltages, sedimentation time on sample stage simultaneously
For 125 seconds, obtained ferrum film thickness was 5 nanometers.
(5) silicon chip that the deposition obtaining step (4) has 5 nanometers of iron catalysts is put in high quartz tube furnace, first will
Catalyst heat treatment 1 hour under the conditions of 400sccm hydrogen, 853k, after under the conditions of 150sccm ammonia, 1023k process 10 points
Clock to lift catalyst activity, finally growth at atmosphere CNT under the conditions of 87sccm acetylene, 600sccm hydrogen, 1023k
Array, growth time is 30 minutes.
(6) carbon nano pipe array obtaining step (5) is put in the process chamber of radio-frequency unit, is passed through high-purity hydrogen
(5n), adjusting reative cell air pressure is 100pa, and substrate is heated to 1000k, waits air pressure and temperature stabilization；
(7) start radio frequency source on the basis of step (6), regulation radio-frequency power is 30-50w, start to process CNT
Array, process time is 10-30 hour, and final gained is the carbon nano pipe array of carbon nano-particle cladding.
(8) silicon single crystal flake of the carbon nano pipe array of carbon nano-particle cladding is had as base with the growth obtained by step (7)
Bottom assembles field electronic emitter according to a conventional method, specific as follows: will grow the carbon nanometer having carbon nano-particle cladding with conducting resinl
The silicon single crystal flake of pipe array sticks to thickness and is about on 2 millimeters of copper metal electrode as field-transmitting cathode, and by minus earth,
As anode, two electrode thickness are 200 microns of ring dress politef isolation to the copper coin being about 2 millimeters with a thickness, bear
Carry positive bias on positive plate so that it may obtain stable field-electron emission, the big I of Flied emission electric current is passed through to change positive bias
Size is adjusting；The carbon nano-pipe array of the carbon nano-particle cladding of the growth with silicon single crystal flake arranges the filed emission cathode material as base
Threshold electric field (Flied emission electric current density be 10 μ a/cm2Required electric field) only v/ μm of 0.90-1.10, threshold field
(Flied emission electric current density is 10 ma/cm2Required electric field) only v/ μm of 1.44-1.63, maximum field emission can
Reach 46.78 ma/cm2, and there is good field emission stability.
The preparation method of carbon nano-tube array field emission cathode of carbon nano-particle cladding disclosed by the invention and existing skill
Art is compared it and is advantageous in that:
The carbon nano-tube array field emission cathode of the carbon nano-particle cladding of this method preparation has very low unlatching field
(v/ μm of 0.90-1.10) and threshold field (v/ μm of 1.44-1.63), maximum field emission is up to 46.78 ma/cm2,
And field emission stability is good (in 10 hours, curent change amplitude is very little), these indexs compare original undressed carbon
Nano-tube array is all greatly improved.Method of plasma processing used, technique is by a relatively simple, to equipment requirements not
Height, and other impurity will not be introduced in CNT, there is higher practical value.
Brief description:
Fig. 1 is the process flow diagram that the present invention prepares carbon nano-particle enveloped carbon nanometer tube array, is broadly divided into system
Standby clean silicon wafer substrate, magnetron sputtering method Precipitated iron catalyst, thermal chemical vapor deposition method prepare carbon nano pipe array, low work(
Four parts such as rate radio frequency hydrogen plasma process carbon nano pipe array；
Fig. 2 is the scanning electron microscopic picture of the carbon nano pipe array as shown in embodiment 1 prepared by experiment condition, and shown carbon is received
Nanotube length is about 23 microns, and upper right corner illustration show the scanning electron microscopic picture on carbon nano pipe array top, lower right corner illustration
It show the scanning electron microscopic picture in the middle part of CNT；
Fig. 3 is the structural representation of radio-frequency unit used in the present invention；Hydrogen purity used is 5n, and heater is self-control molybdenum
Silk heater, combines the unit evacuation with " molecular pump+mechanical pump "；
Fig. 4 is the scanning electron microscopic picture of the carbon nano pipe array of carbon nano-particle cladding of preparation under different condition, gained
Carbon nano-particle diameter is mostly in 15-30 nanometer, comprising:
41. press embodiment 1 condition (radio-frequency power: 30w；Process time: 10 hours) prepared by carbon nano-particle cladding
Carbon nano pipe array scanning electron microscopic picture, upper right and lower right corner illustration are corresponding high power scanning electron microscopic picture, correspond to
In figure square frame identification division；
42. press embodiment 2 condition (radio-frequency power: 30w；Process time: 20 hours) prepared by carbon nano-particle cladding
Carbon nano pipe array scanning electron microscopic picture；
43. press embodiment 3 condition (radio-frequency power: 30w；Process time: 30 hours) prepared by carbon nano-particle cladding
Carbon nano pipe array scanning electron microscopic picture；
Fig. 5 show the structural representation of fine vacuum Flied emission tester, for testing prepared carbon in each embodiment
The field emission performance of the carbon nano pipe array of nano-particle cladding；This device is that the Flied emission of a conventional diode configuration is surveyed
Trial assembly is put: with prepared field emmision material as negative electrode, is about 10 centimetres of corrosion resistant plate as anode with diameter, anode position essence
Really adjustable, two die openings remain 2 millimeters；In test, by minus earth, in the adjustable positive bias of plate-load 0-10kv；Test
Data is recorded automatically by computer；
Fig. 6 is the field emission performance figure of the carbon nano pipe array of carbon nano-particle cladding prepared at different conditions, tool
Body include embodiment 1, embodiment 2, in embodiment 3 prepared sample and original carbon nanotubes array field emission performance comparison,
What it characterized is the variation relation that Flied emission electric current density increases with electric field strength, whereinj thRepresent is that threshold field is sent out
Radio current density, its size is 10 ma/cm2；
Fig. 7 is the carbon nano pipe array of carbon nano-particle cladding and the original carbon nanotubes array prepared by embodiment 2
Field emission stability figure, sign is in the case that extra electric field is constant, Flied emission electric current density relation over time.
Specific embodiment
The present invention is described in more detail with reference to the accompanying drawings and examples, but the invention is not restricted to these embodiments.
Wherein used silicon single crystal flake, dehydrated alcohol, acetone, Fluohydric acid., high-purity hydrogen, high purity acetylene gas, high-purity ammonia, high-purity argon
Gas, high purity iron target etc. are commercially available.Ultrasonic cleaning, metal vapor vacuum arc source (mevva source), magnetron sputtering, high temperature pipe
The devices such as formula stove, radio frequency, Flied emission tester are commercially available.
It is the process flow diagram that the present invention prepares the carbon nano pipe array of carbon nano-particle cladding shown in Fig. 1, point
For preparation clean silicon wafer substrate, magnetron sputtering method Precipitated iron catalyst, thermal chemical vapor deposition method prepare carbon nano pipe array,
Four parts such as low-power radio frequency hydrogen plasma process carbon nano pipe array, the relevant sample preparation of following examples partly equal
By the execution of this four step.
Embodiment 1
(1) prepare clean silicon wafer substrate:
First silicon chip is cut into 2cm × 2cm small pieces, each ultrasonic (50w) in deionized water, acetone and dehydrated alcohol successively
Cleaning 10 minutes, then silicon wafer is put in the Fluohydric acid. that volume ratio is 4% soak 5 minutes, obtain totally pollution-free and no dioxy
The substrate of SiClx cover layer.
(2) magnetron sputtering method Precipitated iron catalyst:
Being deposited in magnetic control sputtering device (commercially available) of iron catalyst is carried out.Before this, first by silicon single crystal flake in gold
Belong to and carry out in steam-to-vacuum arc ion source (mevva source, commercially available) carrying and can bombard pretreatment by iron ion, iron ion energy is about
15kev, line is 10 milliamperes, and process time is 15 minutes, and this process can effectively lift the combination between CNT and silicon base
Power；Then the silicon wafer bombarding load energy iron ion is placed on sample stage, first to vacuum chamber to about 8 × 10-5Pa,
With despumation gaseous contamination, then pass to high-purity (5n) argon, regulation chamber pressure is 1.0pa；During deposition, DC source electricity
Flow for 60 milliamperes, 150 volts of back bias voltages are added on sample stage simultaneously, sedimentation time is 125 seconds, and obtained ferrum film thickness is 5 nanometers.
(3) thermal chemical vapor deposition method prepares carbon nano pipe array:
Being grown in of carbon nano pipe array completes in high temperature process furnances (commercially available), and method therefor is traditional heat chemistry gas
Phase sedimentation, and whole process completes at ambient pressure.The silicon wafer first deposition being had 5 nanometers of iron catalysts inserts tubular type hearthstone
On sample stage in English pipe, after having closed quartz ampoule, by iron catalyst under the conditions of 400sccm hydrogen, 853k heat treatment 1 hour；
Process 10 minutes afterwards to lift catalyst activity under the conditions of 150sccm ammonia, 1023k；Last 87sccm acetylene,
Carbon nano pipe array is grown, growth time is 30 minutes under the conditions of 600sccm hydrogen, 1023k.It is in this condition shown in Fig. 2
, it can be seen that length of carbon nanotube is about 23 microns (Fig. 2), top is curved for the scanning electron microscopic picture of lower gained carbon nano pipe array
Bent (Fig. 2 upper right corner illustration), but middle part array is preferably (Fig. 2 lower right corner illustration), and smooth surface.
(4) low-power radio frequency hydrogen plasma process carbon nano pipe array:
Hydrogen plasma process carbon nano-pipe array is listed in radio-frequency unit (commercially available) and completes, and is this device shown in Fig. 3
Structural representation.First prepared carbon nano pipe array is placed on graphite sample platform, to process chamber forvacuum extremely
About 8 × 10-4Pa, then heats to substrate, heating rate is about 60k/min in hydrogen (purity is 5n) atmosphere, until
Temperature stabilization is till 1000k, and adjusts air pressure for 100pa, after temperature and air pressure are all stable, starts radio frequency source, regulation is penetrated
Frequency power is 30w, and process time is 10 hours.It is the carbon of the carbon nano-particle cladding of gained under this condition shown in Fig. 4-41
The scanning electron microscopic picture of nano-tube array, compared with original carbon nanotubes shown in Fig. 2, CNT entirety morphology change is little,
But surface is coated by carbon nano-particle, granule is less, in 15-20 nanometer more than diameter, from Fig. 4-41 upper right and lower right corner high power
Scanning electron microscopic picture can be clearly seen, completely different with the smooth surface (Fig. 2 illustration) of original carbon nanotubes, these Carbon Nanohorns
Rise and be all likely to become potential effective field launch point.
(5) field emission performance test:
The field emission performance test of the carbon nano pipe array of carbon nano-particle cladding (has city in fine vacuum Flied emission tester
Sell) in complete, be the structural representation of this test device shown in Fig. 5.In test cabinet, vacuum maintains about 1 × 10-7Pa(uses
Normally opened titanium getter pump evacuation).The carbon nano pipe array sample conducting resinl of prepared carbon nano-particle cladding is adhered to
On copper sample platform, in this, as field-transmitting cathode, and by minus earth；Anode is the rustless steel circle that a diameter is about 10 centimetres
Plate, anode and cathode keeping parallelism, spacing is 2 millimeters；During test, the adjustable positive bias of 0-10kv is loaded on anode, bias speedup is permanent
It is set to 500 v/min, test result be recorded in computer by Automatic Program.As prepare at different conditions shown in Fig. 6
The field emission performance figure of the carbon nano pipe array of carbon nano-particle cladding, specifically include the present embodiment, embodiment 2, in embodiment 3
The comparison of prepared sample and original carbon nanotubes array field emission performance, what it characterized is Flied emission electric current density with powering up outward
The variation relation that field intensity increases.As can be seen that the carbon nano-particle bag through gained after hydrogen plasma process 10 hours under 30w
The unlatching field of the carbon nano pipe array covering, threshold field and maximum field emission are respectively 1.10 v/ μm, 1.63 v/ μm
With 37.24 ma/cm2, it is better than 1.24 v/ μm, 1.76 v/ μm and 21.90 ma/cm of original carbon nanotubes2.Flied emission
Can lifting be attributable to long-time low-power hydrogen plasma process after the increasing, greatly of carbon nano tube surface effective field launch point
The carbon nano-particle of amount all can become effective field launch point, and Flied emission electric current density is compared original carbon nanotubes and only had most advanced and sophisticated transmitting
Electronics undoubtedly will be substantially improved.
(6) field electronic emitter assembling (conventional sectional method):
With conducting resinl, the silicon single crystal flake growing the carbon nano pipe array having carbon nano-particle cladding being sticked to thickness is 2 millis
On the copper electrode of rice, as field-transmitting cathode, and by minus earth, anode is the copper plate electrode that a thickness is 2 millimeters, cloudy
The ring dress politef that anode keeping parallelism is 200 microns with thickness separates, and load positive bias is on positive plate so that it may obtain
Field-electron emission that must be stable, the control of Flied emission electric current density size can be realized by adjusting positive plate and biasing.
Embodiment 2
(1) prepare clean silicon wafer substrate:
First silicon chip is cut into 2cm × 2cm small pieces, each ultrasonic (50w) in deionized water, acetone and dehydrated alcohol successively
Cleaning 10 minutes, then silicon wafer is put in the Fluohydric acid. that volume ratio is 4% soak 5 minutes, obtain totally pollution-free and no dioxy
The substrate of SiClx cover layer.
(2) magnetron sputtering method Precipitated iron catalyst:
Being deposited in magnetic control sputtering device (commercially available) of iron catalyst is carried out.Before this, first by silicon single crystal flake in gold
Belong to and carry out in steam-to-vacuum arc ion source (mevva source, commercially available) carrying and can bombard pretreatment by iron ion, iron ion energy is about
15kev, line is 10 milliamperes, and process time is 15 minutes, and this process can effectively lift the combination between CNT and silicon base
Power；Then the silicon wafer bombarding load energy iron ion is placed on sample stage, first to vacuum chamber to about 8 × 10-5Pa,
With despumation gaseous contamination, then pass to high-purity (5n) argon, regulation chamber pressure is 1.0pa；During deposition, DC source electricity
Flow for 60 milliamperes, 150 volts of back bias voltages are added on sample stage simultaneously, sedimentation time is 125 seconds, and obtained ferrum film thickness is 5 nanometers.
(3) thermal chemical vapor deposition method prepares carbon nano pipe array:
Being grown in of carbon nano pipe array completes in high temperature process furnances (commercially available), and method therefor is traditional heat chemistry gas
Phase sedimentation, and whole process completes at ambient pressure.The silicon wafer first deposition being had 5 nanometers of iron catalysts inserts tubular type hearthstone
On sample stage in English pipe, after having closed quartz ampoule, by iron catalyst under the conditions of 400sccm hydrogen, 853k heat treatment 1 hour；
Process 10 minutes afterwards to lift catalyst activity under the conditions of 150sccm ammonia, 1023k；Last 87sccm acetylene,
Carbon nano pipe array is grown, growth time is 30 minutes under the conditions of 600sccm hydrogen, 1023k.
(4) low-power radio frequency hydrogen plasma process carbon nano pipe array:
Hydrogen plasma process carbon nano-pipe array is listed in radio-frequency unit (commercially available) and completes, and is this device shown in Fig. 3
Structural representation.First prepared carbon nano pipe array is placed on graphite sample platform, to process chamber forvacuum extremely
About 8 × 10-4Pa, then heats to substrate, heating rate is about 60k/min in hydrogen (purity is 5n) atmosphere, until
Temperature stabilization is till 1000k, and adjusts air pressure for 100pa, after temperature and air pressure are all stable, starts radio frequency source, regulation is penetrated
Frequency power is 30w, and process time is 20 hours.It is the carbon nano-particle cladding of gained in the present embodiment shown in Fig. 4-42
The scanning electron microscopic picture of carbon nano pipe array, compared with original carbon nanotubes shown in Fig. 2, CNT entirety morphology change is not
Greatly, but surface is coated by carbon nano-particle, particle diameter compare 30w, 10 hours process after gained CNT (Fig. 4-
41) have increased slightly, mostly in 20-30 nanometer, completely different with the smooth surface (Fig. 2 illustration) of original carbon nanotubes, these carbon
Nanometer projection is all likely to become potential effective field launch point.
(5) field emission performance test:
The field emission performance test of the carbon nano pipe array of carbon nano-particle cladding (has city in fine vacuum Flied emission tester
Sell) in complete, be the structural representation of this test device shown in Fig. 5.In test cabinet, vacuum maintains about 1 × 10-7Pa(uses
Normally opened titanium getter pump evacuation).The carbon nano pipe array sample conducting resinl of prepared carbon nano-particle cladding is adhered to
On copper sample platform, in this, as field-transmitting cathode, and by minus earth；Anode is the rustless steel circle that a diameter is about 10 centimetres
Plate, anode and cathode keeping parallelism, spacing is 2 millimeters；During test, the adjustable positive bias of 0-10kv is loaded on anode, bias speedup is permanent
It is set to 500v/min, test result be recorded in computer by Automatic Program.From fig. 6, it can be seen that through hydrogen plasma under 30w
The unlatching field of carbon nano pipe array of carbon nano-particle cladding of gained, threshold field and maximum field emission current after processing 20 hours
Density is respectively 0.90 v/ μm, 1.44 v/ μm and 43.42 ma/cm2, 1.24 v/ μ of original carbon nanotubes to be far superior to
M, 1.76 v/ μm and 21.90 ma/cm2, also 30w to be better than, process within 10 hours after 1.10 v/ μm of carbon nano pipe array,
1.63 v/ μm and 37.24 ma/cm2.Being substantially improved of field emission performance is attributable at long-time low-power hydrogen plasma
The increasing of carbon nano tube surface effective field launch point after reason, substantial amounts of carbon nano-particle all can become effective field launch point, and field is sent out
Radio current density is compared the only most advanced and sophisticated launching electronics of original carbon nanotubes and undoubtedly will be substantially improved.Fig. 7 show in the present embodiment
The prepared carbon nano pipe array of carbon nano-particle cladding and the field emission stability of original unprocessed carbon nano pipe array
Figure, sign is under constant External Electrical Field, Flied emission electric current density relation over time.As can be seen that this enforcement
The carbon nano pipe array that in example, prepared carbon nano-particle coats has more steady than the more preferable Flied emission of original carbon nanotubes array
Qualitative, in test in 10 hours, (mean field emission is 12.25 ma/cm2), Flied emission electric current density is not substantially
Decay, fluctuation also very little, but original carbon nanotubes sample in test in 10 hours, (mean field emission is 9.80 ma/
cm2), electric current density decay about 17%.Although the mean field emission of the two is all in threshold field emission
(j th, 10 ma/cm2) near, but in test, the constant electric field strength of carbon nano-particle enveloped carbon nanometer tube sample is only
1.50 v/ μm, much smaller than 1.80 v/ μm of original carbon nanotubes sample, the reduction of this running voltage is to practical application right and wrong
Often important.As can be seen here, long-time high temperature and corona treatment greatly improve carbon nano pipe array Flied emission steady
Qualitative.
(6) field electronic emitter assembling (conventional sectional method):
With conducting resinl, the silicon single crystal flake growing the carbon nano pipe array having carbon nano-particle cladding being sticked to thickness is 2 millis
On the copper electrode of rice, as field-transmitting cathode, and by minus earth, anode is the copper plate electrode that a thickness is 2 millimeters, cloudy
The ring dress politef that anode keeping parallelism is 200 microns with thickness separates, and load positive bias is on positive plate so that it may obtain
Field-electron emission that must be stable, the control of Flied emission electric current density size can be realized by adjusting positive plate and biasing.
Embodiment 3
(1) prepare clean silicon wafer substrate:
First silicon chip is cut into 2cm × 2cm small pieces, each ultrasonic (50w) in deionized water, acetone and dehydrated alcohol successively
Cleaning 10 minutes, then silicon wafer is put in the Fluohydric acid. that volume ratio is 4% soak 5 minutes, obtain totally pollution-free and no dioxy
The substrate of SiClx cover layer.
(2) magnetron sputtering method Precipitated iron catalyst:
Being deposited in magnetic control sputtering device (commercially available) of iron catalyst is carried out.Before this, first by silicon single crystal flake in gold
Belong to and carry out in steam-to-vacuum arc ion source (mevva source, commercially available) carrying and can bombard pretreatment by iron ion, iron ion energy is about
15kev, line is 10 milliamperes, and process time is 15 minutes, and this process can effectively lift the combination between CNT and silicon base
Power；Then the silicon wafer bombarding load energy iron ion is placed on sample stage, first to vacuum chamber to about 8 × 10-5Pa,
With despumation gaseous contamination, then pass to high-purity (5n) argon, regulation chamber pressure is 1.0pa；During deposition, DC source electricity
Flow for 60 milliamperes, 150 volts of back bias voltages are added on sample stage simultaneously, sedimentation time is 125 seconds, and obtained ferrum film thickness is 5 nanometers.
(3) thermal chemical vapor deposition method prepares carbon nano pipe array:
Being grown in of carbon nano pipe array completes in high temperature process furnances (commercially available), and method therefor is traditional heat chemistry gas
Phase sedimentation, and whole process completes at ambient pressure.The silicon wafer first deposition being had 5 nanometers of iron catalysts inserts tubular type hearthstone
On sample stage in English pipe, after having closed quartz ampoule, by iron catalyst under the conditions of 400sccm hydrogen, 853k heat treatment 1 hour；
Process 10 minutes afterwards to lift catalyst activity under the conditions of 150sccm ammonia, 1023k；Last 87sccm acetylene,
Carbon nano pipe array is grown, growth time is 30 minutes under the conditions of 600sccm hydrogen, 1023k.
(4) low-power radio frequency hydrogen plasma process carbon nano pipe array:
Hydrogen plasma process carbon nano-pipe array is listed in radio-frequency unit (commercially available) and completes, and is this device shown in Fig. 3
Structural representation.First prepared carbon nano pipe array is placed on graphite sample platform, to process chamber forvacuum extremely
About 8 × 10-4Pa, then heats to substrate, heating rate is about 60k/min in hydrogen (purity is 5n) atmosphere, until
Temperature stabilization is till 1000k, and adjusts air pressure for 100pa, after temperature and air pressure are all stable, starts radio frequency source, regulation is penetrated
Frequency power is 30w, and process time is 30 hours.It is the carbon of the carbon nano-particle cladding in the present embodiment gained shown in Fig. 4-43
The scanning electron microscopic picture of nano-tube array, compared with original carbon nanotubes shown in Fig. 2, CNT entirety morphology change is little,
But surface is coated by carbon nano-particle, particle diameter compares 30w, 10 hours (Fig. 4-41) and 30w, 20 hours (Fig. 4-42) places
After reason, the CNT of gained is intended to little, and mostly in 15-20 nanometer, and grain boundary is unintelligible, but with original carbon nanotubes
Smooth surface (Fig. 2 illustration) is completely different, and these Carbon Nanohorns rise and are all likely to become potential effective field launch point.
(5) field emission performance test:
The field emission performance test of the carbon nano pipe array of carbon nano-particle cladding (has city in fine vacuum Flied emission tester
Sell) in complete, be the structural representation of this test device shown in Fig. 5.In test cabinet, vacuum maintains about 1 × 10-7Pa(uses
Normally opened titanium getter pump evacuation).The carbon nano pipe array sample conducting resinl of prepared carbon nano-particle cladding is adhered to
On copper sample platform, in this, as field-transmitting cathode, and by minus earth；Anode is the rustless steel circle that a diameter is about 10 centimetres
Plate, anode and cathode keeping parallelism, spacing is 2 millimeters；During test, the adjustable positive bias of 0-10kv is loaded on anode, bias speedup is permanent
It is set to 500v/min, test result be recorded in computer by Automatic Program.From fig. 6, it can be seen that through hydrogen plasma under 30w
The unlatching field of carbon nano pipe array of carbon nano-particle cladding of gained, threshold field and maximum field emission current after processing 30 hours
Density is respectively 1.02 v/ μm, 1.59 v/ μm and 35.44 ma/cm2, be better than 1.24 v/ μm of original carbon nanotubes,
1.76 v/ μm and 21.90 ma/cm2.After the lifting of field emission performance is attributable to long-time low-power hydrogen plasma process
The increasing of carbon nano tube surface effective field launch point, substantial amounts of carbon nano-particle all can become effective field launch point, Flied emission electricity
Current density is compared the only most advanced and sophisticated launching electronics of original carbon nanotubes and undoubtedly will be substantially improved.
(6) field electronic emitter assembling (conventional sectional method):
With conducting resinl, the silicon single crystal flake growing the carbon nano pipe array having carbon nano-particle cladding being sticked to thickness is 2 millis
On the copper electrode of rice, as field-transmitting cathode, and by minus earth, anode is the copper plate electrode that a thickness is 2 millimeters, cloudy
The ring dress politef that anode keeping parallelism is 200 microns with thickness separates, and load positive bias is on positive plate so that it may obtain
Field-electron emission that must be stable, the control of Flied emission electric current density size can be realized by adjusting positive plate and biasing.
Embodiment 4
(1) prepare clean silicon wafer substrate:
First silicon chip is cut into 2cm × 2cm small pieces, each ultrasonic (50w) in deionized water, acetone and dehydrated alcohol successively
Cleaning 10 minutes, then silicon wafer is put in the Fluohydric acid. that volume ratio is 4% soak 5 minutes, obtain totally pollution-free and no dioxy
The substrate of SiClx cover layer.
(2) magnetron sputtering method Precipitated iron catalyst:
Being deposited in magnetic control sputtering device (commercially available) of iron catalyst is carried out.Before this, first by silicon single crystal flake in gold
Belong to and carry out in steam-to-vacuum arc ion source (mevva source, commercially available) carrying and can bombard pretreatment by iron ion, iron ion energy is about
15kev, line is 10 milliamperes, and process time is 15 minutes, and this process can effectively lift the combination between CNT and silicon base
Power；Then the silicon wafer bombarding load energy iron ion is placed on sample stage, first to vacuum chamber to about 8 × 10-5Pa,
With despumation gaseous contamination, then pass to high-purity (5n) argon, regulation chamber pressure is 1.0pa；During deposition, DC source electricity
Flow for 60 milliamperes, 150 volts of back bias voltages are added on sample stage simultaneously, sedimentation time is 125 seconds, and obtained ferrum film thickness is 5 nanometers.
(3) thermal chemical vapor deposition method prepares carbon nano pipe array:
Being grown in of carbon nano pipe array completes in high temperature process furnances (commercially available), and method therefor is traditional heat chemistry gas
Phase sedimentation, and whole process completes at ambient pressure.The silicon wafer first deposition being had 5 nanometers of iron catalysts inserts tubular type hearthstone
On sample stage in English pipe, after having closed quartz ampoule, by iron catalyst under the conditions of 400sccm hydrogen, 853k heat treatment 1 hour；
Process 10 minutes afterwards to lift catalyst activity under the conditions of 150sccm ammonia, 1023k；Last 87sccm acetylene,
Carbon nano pipe array is grown, growth time is 30 minutes under the conditions of 600sccm hydrogen, 1023k.
(4) low-power radio frequency hydrogen plasma process carbon nano pipe array:
Hydrogen plasma process carbon nano-pipe array is listed in radio-frequency unit (commercially available) and completes, and is this device shown in Fig. 3
Structural representation.First prepared carbon nano pipe array is placed on graphite sample platform, to process chamber forvacuum extremely
About 8 × 10-4Pa, then heats to substrate, heating rate is about 60k/min in hydrogen (purity is 5n) atmosphere, until
Temperature stabilization is till 1000k, and adjusts air pressure for 100pa, after temperature and air pressure are all stable, starts radio frequency source, regulation is penetrated
Frequency power is 40w, and process time is 10 hours.
(5) field emission performance test:
The field emission performance test of the carbon nano pipe array of carbon nano-particle cladding (has city in fine vacuum Flied emission tester
Sell) in complete, be the structural representation of this test device shown in Fig. 5.In test cabinet, vacuum maintains about 1 × 10-7Pa(uses
Normally opened titanium getter pump evacuation).The carbon nano pipe array sample conducting resinl of prepared carbon nano-particle cladding is adhered to
On copper sample platform, in this, as field-transmitting cathode, and by minus earth；Anode is the rustless steel circle that a diameter is about 10 centimetres
Plate, anode and cathode keeping parallelism, spacing is 2 millimeters；During test, the adjustable positive bias of 0-10kv is loaded on anode, bias speedup is permanent
It is set to 500v/min, test result be recorded in computer by Automatic Program.The carbon nano-particle cladding of the present embodiment gained
The unlatching field of carbon nano pipe array, threshold field and maximum field emission be respectively 1.04 v/ μm, 1.60 v/ μm and
36.12 ma/cm2, it is better than 1.24 v/ μm, 1.76 v/ μm and 21.90 ma/cm of original carbon nanotubes2.Field emission performance
Lifting be attributable to long-time low-power hydrogen plasma process after the increasing, in a large number of carbon nano tube surface effective field launch point
Carbon nano-particle all can become effective field launch point, Flied emission electric current density is compared original carbon nanotubes and is only had most advanced and sophisticated transmitting electricity
Son undoubtedly will be substantially improved.
(6) field electronic emitter assembling (conventional sectional method):
With conducting resinl, the silicon single crystal flake growing the carbon nano pipe array having carbon nano-particle cladding being sticked to thickness is 2 millis
On the copper electrode of rice, as field-transmitting cathode, and by minus earth, anode is the copper plate electrode that a thickness is 2 millimeters, cloudy
The ring dress politef that anode keeping parallelism is 200 microns with thickness separates, and load positive bias is on positive plate so that it may obtain
Field-electron emission that must be stable, the control of Flied emission electric current density size can be realized by adjusting positive plate and biasing.
Embodiment 5
(1) prepare clean silicon wafer substrate:
First silicon chip is cut into 2cm × 2cm small pieces, each ultrasonic (50w) in deionized water, acetone and dehydrated alcohol successively
Cleaning 10 minutes, then silicon wafer is put in the Fluohydric acid. that volume ratio is 4% soak 5 minutes, obtain totally pollution-free and no dioxy
The substrate of SiClx cover layer.
(2) magnetron sputtering method Precipitated iron catalyst:
Being deposited in magnetic control sputtering device (commercially available) of iron catalyst is carried out.Before this, first by silicon single crystal flake in gold
Belong to and carry out in steam-to-vacuum arc ion source (mevva source, commercially available) carrying and can bombard pretreatment by iron ion, iron ion energy is about
15kev, line is 10 milliamperes, and process time is 15 minutes, and this process can effectively lift the combination between CNT and silicon base
Power；Then the silicon wafer bombarding load energy iron ion is placed on sample stage, first to vacuum chamber to about 8 × 10-5Pa,
With despumation gaseous contamination, then pass to high-purity (5n) argon, regulation chamber pressure is 1.0pa；During deposition, DC source electricity
Flow for 60 milliamperes, 150 volts of back bias voltages are added on sample stage simultaneously, sedimentation time is 125 seconds, and obtained ferrum film thickness is 5 nanometers.
(3) thermal chemical vapor deposition method prepares carbon nano pipe array:
Being grown in of carbon nano pipe array completes in high temperature process furnances (commercially available), and method therefor is traditional heat chemistry gas
Phase sedimentation, and whole process completes at ambient pressure.The silicon wafer first deposition being had 5 nanometers of iron catalysts inserts tubular type hearthstone
On sample stage in English pipe, after having closed quartz ampoule, by iron catalyst under the conditions of 400sccm hydrogen, 853k heat treatment 1 hour；
Process 10 minutes afterwards to lift catalyst activity under the conditions of 150sccm ammonia, 1023k；Last 87sccm acetylene,
Carbon nano pipe array is grown, growth time is 30 minutes under the conditions of 600sccm hydrogen, 1023k.
(4) low-power radio frequency hydrogen plasma process carbon nano pipe array:
Hydrogen plasma process carbon nano-pipe array is listed in radio-frequency unit (commercially available) and completes, and is this device shown in Fig. 3
Structural representation.First prepared carbon nano pipe array is placed on graphite sample platform, to process chamber forvacuum extremely
About 8 × 10-4Pa, then heats to substrate, heating rate is about 60k/min in hydrogen (purity is 5n) atmosphere, until
Temperature stabilization is till 1000k, and adjusts air pressure for 100pa, after temperature and air pressure are all stable, starts radio frequency source, regulation is penetrated
Frequency power is 40w, and process time is 20 hours.
(5) field emission performance test:
The field emission performance test of the carbon nano pipe array of carbon nano-particle cladding (has city in fine vacuum Flied emission tester
Sell) in complete, be the structural representation of this test device shown in Fig. 5.In test cabinet, vacuum maintains about 1 × 10-7Pa(uses
Normally opened titanium getter pump evacuation).The carbon nano pipe array sample conducting resinl of prepared carbon nano-particle cladding is adhered to
On copper sample platform, in this, as field-transmitting cathode, and by minus earth；Anode is the rustless steel circle that a diameter is about 10 centimetres
Plate, anode and cathode keeping parallelism, spacing is 2 millimeters；During test, the adjustable positive bias of 0-10kv is loaded on anode, bias speedup is permanent
It is set to 500v/min, test result be recorded in computer by Automatic Program.The carbon nano-particle cladding of the present embodiment gained
The unlatching field of carbon nano pipe array, threshold field and maximum field emission be respectively 0.96 v/ μm, 1.52 v/ μm and
41.48 ma/cm2, it is better than 1.24 v/ μm, 1.76 v/ μm and 21.90 ma/cm of original carbon nanotubes2.Field emission performance
Lifting be attributable to long-time low-power hydrogen plasma process after the increasing, in a large number of carbon nano tube surface effective field launch point
Carbon nano-particle all can become effective field launch point, Flied emission electric current density is compared original carbon nanotubes and is only had most advanced and sophisticated transmitting electricity
Son undoubtedly will be substantially improved.
(6) field electronic emitter assembling (conventional sectional method):
With conducting resinl, the silicon single crystal flake growing the carbon nano pipe array having carbon nano-particle cladding being sticked to thickness is 2 millis
On the copper electrode of rice, as field-transmitting cathode, and by minus earth, anode is the copper plate electrode that a thickness is 2 millimeters, cloudy
The ring dress politef that anode keeping parallelism is 200 microns with thickness separates, and load positive bias is on positive plate so that it may obtain
Field-electron emission that must be stable, the control of Flied emission electric current density size can be realized by adjusting positive plate and biasing.
Embodiment 6
(1) prepare clean silicon wafer substrate:
First silicon chip is cut into 2cm × 2cm small pieces, each ultrasonic (50w) in deionized water, acetone and dehydrated alcohol successively
Cleaning 10 minutes, then silicon wafer is put in the Fluohydric acid. that volume ratio is 4% soak 5 minutes, obtain totally pollution-free and no dioxy
The substrate of SiClx cover layer.
(2) magnetron sputtering method Precipitated iron catalyst:
Being deposited in magnetic control sputtering device (commercially available) of iron catalyst is carried out.Before this, first by silicon single crystal flake in gold
Belong to and carry out in steam-to-vacuum arc ion source (mevva source, commercially available) carrying and can bombard pretreatment by iron ion, iron ion energy is about
15kev, line is 10 milliamperes, and process time is 15 minutes, and this process can effectively lift the combination between CNT and silicon base
Power；Then the silicon wafer bombarding load energy iron ion is placed on sample stage, first to vacuum chamber to about 8 × 10-5Pa,
With despumation gaseous contamination, then pass to high-purity (5n) argon, regulation chamber pressure is 1.0pa；During deposition, DC source electricity
Flow for 60 milliamperes, 150 volts of back bias voltages are added on sample stage simultaneously, sedimentation time is 125 seconds, and obtained ferrum film thickness is 5 nanometers.
(3) thermal chemical vapor deposition method prepares carbon nano pipe array:
Being grown in of carbon nano pipe array completes in high temperature process furnances (commercially available), and method therefor is traditional heat chemistry gas
Phase sedimentation, and whole process completes at ambient pressure.The silicon wafer first deposition being had 5 nanometers of iron catalysts inserts tubular type hearthstone
On sample stage in English pipe, after having closed quartz ampoule, by iron catalyst under the conditions of 400sccm hydrogen, 853k heat treatment 1 hour；
Process 10 minutes afterwards to lift catalyst activity under the conditions of 150sccm ammonia, 1023k；Last 87sccm acetylene,
Carbon nano pipe array is grown, growth time is 30 minutes under the conditions of 600sccm hydrogen, 1023k.
(4) low-power radio frequency hydrogen plasma process carbon nano pipe array:
Hydrogen plasma process carbon nano-pipe array is listed in radio-frequency unit (commercially available) and completes, and is this device shown in Fig. 3
Structural representation.First prepared carbon nano pipe array is placed on graphite sample platform, to process chamber forvacuum extremely
About 8 × 10-4Pa, then heats to substrate, heating rate is about 60k/min in hydrogen (purity is 5n) atmosphere, until
Temperature stabilization is till 1000k, and adjusts air pressure for 100pa, after temperature and air pressure are all stable, starts radio frequency source, regulation is penetrated
Frequency power is 50w, and process time is 20 hours.
(5) field emission performance test:
The field emission performance test of the carbon nano pipe array of carbon nano-particle cladding (has city in fine vacuum Flied emission tester
Sell) in complete, be the structural representation of this test device shown in Fig. 5.In test cabinet, vacuum maintains about 1 × 10-7Pa(uses
Normally opened titanium getter pump evacuation).The carbon nano pipe array sample conducting resinl of prepared carbon nano-particle cladding is adhered to
On copper sample platform, in this, as field-transmitting cathode, and by minus earth；Anode is the rustless steel circle that a diameter is about 10 centimetres
Plate, anode and cathode keeping parallelism, spacing is 2 millimeters；During test, the adjustable positive bias of 0-10kv is loaded on anode, bias speedup is permanent
It is set to 500v/min, test result be recorded in computer by Automatic Program.The carbon nano-particle cladding of the present embodiment gained
The unlatching field of carbon nano pipe array, threshold field and maximum field emission be respectively 0.98 v/ μm, 1.51 v/ μm and
40.57 ma/cm2, it is better than 1.24 v/ μm, 1.76 v/ μm and 21.90 ma/cm of original carbon nanotubes2.Field emission performance
Lifting be attributable to long-time low-power hydrogen plasma process after the increasing, in a large number of carbon nano tube surface effective field launch point
Carbon nano-particle all can become effective field launch point, Flied emission electric current density is compared original carbon nanotubes and is only had most advanced and sophisticated transmitting electricity
Son undoubtedly will be substantially improved.
(6) field electronic emitter assembling (conventional sectional method):
With conducting resinl, the silicon single crystal flake growing the carbon nano pipe array having carbon nano-particle cladding being sticked to thickness is 2 millis
On the copper electrode of rice, as field-transmitting cathode, and by minus earth, anode is the copper plate electrode that a thickness is 2 millimeters, cloudy
The ring dress politef that anode keeping parallelism is 200 microns with thickness separates, and load positive bias is on positive plate so that it may obtain
Field-electron emission that must be stable, the control of Flied emission electric current density size can be realized by adjusting positive plate and biasing.
Embodiment 7
(1) prepare clean silicon wafer substrate:
First silicon chip is cut into 2cm × 2cm small pieces, each ultrasonic (50w) in deionized water, acetone and dehydrated alcohol successively
Cleaning 10 minutes, then silicon wafer is put in the Fluohydric acid. that volume ratio is 4% soak 5 minutes, obtain totally pollution-free and no dioxy
The substrate of SiClx cover layer.
(2) magnetron sputtering method Precipitated iron catalyst:
Being deposited in magnetic control sputtering device (commercially available) of iron catalyst is carried out.Before this, first by silicon single crystal flake in gold
Belong to and carry out in steam-to-vacuum arc ion source (mevva source, commercially available) carrying and can bombard pretreatment by iron ion, iron ion energy is about
15kev, line is 10 milliamperes, and process time is 15 minutes, and this process can effectively lift the combination between CNT and silicon base
Power；Then the silicon wafer bombarding load energy iron ion is placed on sample stage, first to vacuum chamber to about 8 × 10-5Pa,
With despumation gaseous contamination, then pass to high-purity (5n) argon, regulation chamber pressure is 1.0pa；During deposition, DC source electricity
Flow for 60 milliamperes, 150 volts of back bias voltages are added on sample stage simultaneously, sedimentation time is 125 seconds, and obtained ferrum film thickness is 5 nanometers.
(3) thermal chemical vapor deposition method prepares carbon nano pipe array:
Being grown in of carbon nano pipe array completes in high temperature process furnances (commercially available), and method therefor is traditional heat chemistry gas
Phase sedimentation, and whole process completes at ambient pressure.The silicon wafer first deposition being had 5 nanometers of iron catalysts inserts tubular type hearthstone
On sample stage in English pipe, after having closed quartz ampoule, by iron catalyst under the conditions of 400sccm hydrogen, 853k heat treatment 1 hour；
Process 10 minutes afterwards to lift catalyst activity under the conditions of 150sccm ammonia, 1023k；Last 87sccm acetylene,
Carbon nano pipe array is grown, growth time is 30 minutes under the conditions of 600sccm hydrogen, 1023k.
(4) low-power radio frequency hydrogen plasma process carbon nano pipe array:
Hydrogen plasma process carbon nano-pipe array is listed in radio-frequency unit (commercially available) and completes, and is this device shown in Fig. 3
Structural representation.First prepared carbon nano pipe array is placed on graphite sample platform, to process chamber forvacuum extremely
About 8 × 10-4Pa, then heats to substrate, heating rate is about 60k/min in hydrogen (purity is 5n) atmosphere, until
Temperature stabilization is till 1000k, and adjusts air pressure for 100pa, after temperature and air pressure are all stable, starts radio frequency source, regulation is penetrated
Frequency power is 35w, and process time is 15 hours.
(5) field emission performance test:
The field emission performance test of the carbon nano pipe array of carbon nano-particle cladding (has city in fine vacuum Flied emission tester
Sell) in complete, be the structural representation of this test device shown in Fig. 5.In test cabinet, vacuum maintains about 1 × 10-7Pa(uses
Normally opened titanium getter pump evacuation).The carbon nano pipe array sample conducting resinl of prepared carbon nano-particle cladding is adhered to
On copper sample platform, in this, as field-transmitting cathode, and by minus earth；Anode is the rustless steel circle that a diameter is about 10 centimetres
Plate, anode and cathode keeping parallelism, spacing is 2 millimeters；During test, the adjustable positive bias of 0-10kv is loaded on anode, bias speedup is permanent
It is set to 500v/min, test result be recorded in computer by Automatic Program.The carbon nano-particle cladding of the present embodiment gained
The unlatching field of carbon nano pipe array, threshold field and maximum field emission be respectively 0.93 v/ μm, 1.46 v/ μm and
46.78 ma/cm2, it is better than 1.24 v/ μm, 1.76 v/ μm and 21.90 ma/cm of original carbon nanotubes2.Field emission performance
Lifting be attributable to long-time low-power hydrogen plasma process after the increasing, in a large number of carbon nano tube surface effective field launch point
Carbon nano-particle all can become effective field launch point, Flied emission electric current density is compared original carbon nanotubes and is only had most advanced and sophisticated transmitting electricity
Son undoubtedly will be substantially improved.
(6) field electronic emitter assembling (conventional sectional method):
With conducting resinl, the silicon single crystal flake growing the carbon nano pipe array having carbon nano-particle cladding being sticked to thickness is 2 millis
On the copper electrode of rice, as field-transmitting cathode, and by minus earth, anode is the copper plate electrode that a thickness is 2 millimeters, cloudy
The ring dress politef that anode keeping parallelism is 200 microns with thickness separates, and load positive bias is on positive plate so that it may obtain
Field-electron emission that must be stable, the control of Flied emission electric current density size can be realized by adjusting positive plate and biasing.
Last it should be noted that, the above exemplary embodiments only listing the present invention.It is apparent that the present invention is not limited to
State embodiment, also many other experiment parameter combined methods, the those of ordinary skill in this research field can be from the present invention
The all scenario directly derived in disclosure or associate, is all considered to be protection scope of the present invention.
Claims (3)
1. a kind of preparation method of the carbon nano-tube array field emission cathode of carbon nano-particle cladding is it is characterised in that utilize radio frequency
Technology produces hydrogen plasma to process the carbon nano pipe array of thermal chemical vapor deposition method preparation, and adjustment radio-frequency power is 30-
50w, base reservoir temperature are 1000k, reative cell air pressure is 100pa, process time is 10-30 hour, final acquisition different-shape
The carbon nano-tube array field emission cathode material of carbon nano-particle cladding；Described carbon nano-particle refers to diameter and is generally
The granule of 15-30 nanometer.
2. the preparation method of the carbon nano-tube array field emission cathode of carbon nano-particle cladding described in claim 1, its feature
It is: the device for producing hydrogen plasma is lower powered radio frequency source or the device of generation low power density hydrogen plasma.
3. the preparation method of the carbon nano-tube array field emission cathode of carbon nano-particle cladding described in claim 1, its feature
It is to carry out as follows:
(1) it is cleaned by ultrasonic each in deionized water, acetone and dehydrated alcohol successively for silicon single crystal flake 10 minutes, ultrasonic power is
50w；
(2) silicon wafer obtaining step (1) is placed in the Fluohydric acid. that volume ratio is 4% and soaks 5 minutes；
(3) silicon wafer that step (2) is obtained carries out carrying in metal vapor vacuum arc source (mevva source) and can bang iron ion
Hit pretreatment, during bombardment, iron ion energy is 15kev, line is 10 milliamperes, process time is 15 minutes；
(4) silicon wafer bombarding the load energy iron ion that step (3) obtains is inserted deposit thickness in magnetic control sputtering device and is received for 5
The iron catalyst of rice；
(5) silicon chip that the deposition obtaining step (4) has 5 nanometers of iron catalysts is put in high quartz tube furnace, first will be catalyzed
Agent heat treatment 1 hour under the conditions of 400sccm hydrogen, 853k, after under the conditions of 150sccm ammonia, 1023k process 10 minutes,
Last growth at atmosphere carbon nano pipe array under the conditions of 87sccm acetylene, 600sccm hydrogen, 1023k, growth time is 30 points
Clock；
(6) carbon nano pipe array obtaining step (5) is put in the process chamber of radio-frequency unit, is passed through 5n high-purity hydrogen, adjusts
Reative cell air pressure is 100pa, and substrate is heated to 1000k, waits air pressure and temperature stabilization；
(7) start radio frequency source on the basis of step (6), regulation radio-frequency power is 30-50w, start to process carbon nano pipe array,
Process time is 10-30 hour, and final gained is the carbon nano pipe array of carbon nano-particle cladding, and as Flied emission
Cathode material assembles field-electron emission device according to a conventional method.
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