GB2409334A - Quantum dot structure having GaAs layers formed at varying partial pressures - Google Patents
Quantum dot structure having GaAs layers formed at varying partial pressures Download PDFInfo
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- GB2409334A GB2409334A GB0329610A GB0329610A GB2409334A GB 2409334 A GB2409334 A GB 2409334A GB 0329610 A GB0329610 A GB 0329610A GB 0329610 A GB0329610 A GB 0329610A GB 2409334 A GB2409334 A GB 2409334A
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- gaas
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- 239000002096 quantum dot Substances 0.000 title claims abstract description 59
- 229910001218 Gallium arsenide Inorganic materials 0.000 title claims abstract description 45
- RBFQJDQYXXHULB-UHFFFAOYSA-N arsane Chemical compound [AsH3] RBFQJDQYXXHULB-UHFFFAOYSA-N 0.000 claims abstract description 16
- 229910000070 arsenic hydride Inorganic materials 0.000 claims abstract description 14
- 239000000758 substrate Substances 0.000 claims abstract description 6
- 238000000034 method Methods 0.000 claims description 14
- 238000002488 metal-organic chemical vapour deposition Methods 0.000 claims 1
- 229910000530 Gallium indium arsenide Inorganic materials 0.000 abstract description 9
- 239000011159 matrix material Substances 0.000 abstract description 6
- 230000005283 ground state Effects 0.000 description 7
- 208000012868 Overgrowth Diseases 0.000 description 4
- 238000009792 diffusion process Methods 0.000 description 4
- 230000000694 effects Effects 0.000 description 4
- 238000004519 manufacturing process Methods 0.000 description 4
- 230000003287 optical effect Effects 0.000 description 4
- 238000001228 spectrum Methods 0.000 description 4
- 150000001875 compounds Chemical class 0.000 description 3
- 230000000877 morphologic effect Effects 0.000 description 3
- 230000009467 reduction Effects 0.000 description 3
- 238000005229 chemical vapour deposition Methods 0.000 description 2
- 230000003247 decreasing effect Effects 0.000 description 2
- 238000000151 deposition Methods 0.000 description 2
- 238000009826 distribution Methods 0.000 description 2
- 230000005281 excited state Effects 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 238000000103 photoluminescence spectrum Methods 0.000 description 2
- 239000002243 precursor Substances 0.000 description 2
- 238000005549 size reduction Methods 0.000 description 2
- 108010076282 Factor IX Proteins 0.000 description 1
- 230000004888 barrier function Effects 0.000 description 1
- 239000000969 carrier Substances 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000003111 delayed effect Effects 0.000 description 1
- 230000008021 deposition Effects 0.000 description 1
- 230000005284 excitation Effects 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 238000003780 insertion Methods 0.000 description 1
- 230000037431 insertion Effects 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 230000005693 optoelectronics Effects 0.000 description 1
- 230000000750 progressive effect Effects 0.000 description 1
- 238000010791 quenching Methods 0.000 description 1
- 230000000171 quenching effect Effects 0.000 description 1
- 238000002310 reflectometry Methods 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 230000003595 spectral effect Effects 0.000 description 1
- 230000009897 systematic effect Effects 0.000 description 1
- 229910002058 ternary alloy Inorganic materials 0.000 description 1
- 230000007704 transition Effects 0.000 description 1
- 238000009736 wetting Methods 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L33/00—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
- H01L33/02—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies
- H01L33/26—Materials of the light emitting region
- H01L33/30—Materials of the light emitting region containing only elements of Group III and Group V of the Periodic Table
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B82—NANOTECHNOLOGY
- B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
- B82Y20/00—Nanooptics, e.g. quantum optics or photonic crystals
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L33/00—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
- H01L33/02—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies
- H01L33/04—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies with a quantum effect structure or superlattice, e.g. tunnel junction
- H01L33/06—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies with a quantum effect structure or superlattice, e.g. tunnel junction within the light emitting region, e.g. quantum confinement structure or tunnel barrier
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S2304/00—Special growth methods for semiconductor lasers
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S5/00—Semiconductor lasers
- H01S5/30—Structure or shape of the active region; Materials used for the active region
- H01S5/34—Structure or shape of the active region; Materials used for the active region comprising quantum well or superlattice structures, e.g. single quantum well [SQW] lasers, multiple quantum well [MQW] lasers or graded index separate confinement heterostructure [GRINSCH] lasers
- H01S5/341—Structures having reduced dimensionality, e.g. quantum wires
- H01S5/3412—Structures having reduced dimensionality, e.g. quantum wires quantum box or quantum dash
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S5/00—Semiconductor lasers
- H01S5/30—Structure or shape of the active region; Materials used for the active region
- H01S5/34—Structure or shape of the active region; Materials used for the active region comprising quantum well or superlattice structures, e.g. single quantum well [SQW] lasers, multiple quantum well [MQW] lasers or graded index separate confinement heterostructure [GRINSCH] lasers
- H01S5/343—Structure or shape of the active region; Materials used for the active region comprising quantum well or superlattice structures, e.g. single quantum well [SQW] lasers, multiple quantum well [MQW] lasers or graded index separate confinement heterostructure [GRINSCH] lasers in AIIIBV compounds, e.g. AlGaAs-laser, InP-based laser
- H01S5/34313—Structure or shape of the active region; Materials used for the active region comprising quantum well or superlattice structures, e.g. single quantum well [SQW] lasers, multiple quantum well [MQW] lasers or graded index separate confinement heterostructure [GRINSCH] lasers in AIIIBV compounds, e.g. AlGaAs-laser, InP-based laser with a well layer having only As as V-compound, e.g. AlGaAs, InGaAs
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- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Computer Hardware Design (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Power Engineering (AREA)
- Manufacturing & Machinery (AREA)
- Nanotechnology (AREA)
- Physics & Mathematics (AREA)
- Life Sciences & Earth Sciences (AREA)
- Biophysics (AREA)
- Optics & Photonics (AREA)
- Crystallography & Structural Chemistry (AREA)
- Led Devices (AREA)
Abstract
A quantum dot (QD) structure 10 for a laser or LED comprises InGaAs QDs 24 embedded into a binary GaAs matrix 22, 24, 26 which is grown on a GaAs substrate 27. The upper binary GaAs layer 22, 24 is grown with a reduced partial pressure of arsine (AsH3). The next layer of QDs 34 may then be grown directly on the GaAs layer, and thus a stack of 10-15 layers can be achieved. The resulting multi-layer structure has reduced overall strain and can provide room temperature long wavelength emission ( / 1.3 žm).
Description
Improved Quantum Dot Structure The present invention relates to quantum
dot lasers and LEDs. More specifically, the present invention relates to a method of creating an InGaAs quantum dot active layer for the realization of lasers and LEDs with improved optical performances.
The fabrication of InGaAs/GaAs quantum dot (QD) based devices is a promising way of extending the optical emission range of traditional GaAsbased optoelectronic devices up to 1.3 micron and beyond. Due to the three-dimensional confinement of the carriers, which leads to atomic-like density of states, QD lasers are known to have improved optical performances when compared to traditional quantum well (QW) lasers. These improvements include both lower threshold current density and improved temperature stability. Self-organized epitaxial growth of QD lasers at wavelengths up to 1.3 micron and above has been achieved and reported in literature by embedding the In(Ga)As QDs in an IN xGaxAs QW ternary alloy, whose x-composition precisely controls the QDs wavelength emission. However, due to the low volume per layer of active QD material, multistacked QD structures are needed for practical laser devices. The insertion of the ternary QW increases the overall strain of the structure, thus limiting the number of QD layers that can be stacked in the active region to approximately 5-6. In fact, with the progressive strain increase of the active layer with the increasing of stacks, a rapid fall in the QDs surface density and shape control is observed, and extended defect are often introduced. Thus, in such a structure only a limited number of stacked quantum dot layers can be grown, resulting in low structure gain and poor device performances.
Both molecular beam expitaxy (MBE) and metal organic chemical vapor deposition (MOCVD) have been used to fabricate In(Ga)As/GaAs QD lasers with emission wavelengths of 1.3 microns. The low gain due to the limited number of stackable QD layers does not allow the active region to overcome cavity losses and thus requires either longer cavities and/or the fabrication of high reflectivity mirrors on the facets of the laser's cavity.
It is an object of the present invention to overcome or at least mitigate the above-mentioned technical problems by providing a method for producing QD active layers able to generate emitter devices for room temperature operations and with a ground state emission wavelength up to and beyond 1.3 microns.
According to the present invention there is provided a quantum dot structure comprising a first GaAs layer having embedded therein a plurality of quantum dots, and a further GaAs layer disposed thereon, wherein said further layer is grown with a reduced partial pressure of AsH3.
According to further aspect of the present invention, there is provided a method for producing a quantum dot structure comprising the steps of growing a plurality of quantum dots in a GaAs matrix, growing a GaAs QW layer over said quantum dots, wherein partial pressure of AsH3 precursors is altered during the growth of GaAs layer.
While the principle advantages and features of the invention have been described above, a greater understanding and appreciation of the invention may be obtained by referring to the drawings and detailed description of an embodiment, presented by way of example only, in which; FIGURE 1 shows a know QD structure with the QDs inserted into an InGaAs matrix, FIGURE 2 - shows the QD structure according to the present invention where the QDs are inserted into a binary GaAs matrix, FIGURE 3 - shows the normalized room temperature PL spectra of samples A, B. C and D overgrown with AsH3 partial pressures of 5.7xlO-, 4.3x10-, 2.8x10-t and 1.4x10-i mbar, respectively and in the insert the ground state emission wavelength (circles) and energy splitting AE o (triangles) as a function of the AsH3 partial pressure, FIGURE 4 - shows the FWHM (circles) measured for the spectra of figures 3 and the ratio between the low temperature and room temperature radiative efficiency (triangles) as a function of the AsH3 partial pressure, and In Figure I a prior art QD structure 10 is shown having a plurality of QDs 14a, 14b, 14c, 14d, 14e disposed into an InxGa(-x)As layer nominally represented in the sketch with numbers 13,14,15. Layers 13, 14 and 15 are, in this example, InxGa(-x)As ternary compound layers. The structure is grown on a GaAs substrate 16. A further GaAs layer 12 is grown on the ternary compound layer 13. This further GaAs layer 12 is needed in order to enable a further layer of QDs to be grown, thus creating a stacked QD structure need to make a laser device. However, the number of QDs present in each further QD layer grown will decrease due to underlying GaAs layer being affected by its underlying InGaAs ternary compound layer. The overall effect of this decrease in the number of QDs is a reduction in power of the resulting device.
In contrast to the QD structure shown in figure 1, the QD structure of the present invention is shown in figure 2. Here the QD structure 20 has a plurality of QDs 24a, 24b, 24c, 24d and 24e embedded directly into a binary GaAs matrix 22, 24, 26, which is grown on a GaAs substrate layer 27. The upper binary GaAs layer 22, 24 must be grown under low AsH3 flow in order to achieve the objection of this invention. The presence of only an upper GaAs layer 22 enables the next layer of QDs (34a-34e) to be grown directly on the GaAs layer without the need for an intermediary layer of InGaAs. This greatly simplifies the steps needed to create the QD stacked structure. Figure 2 shows a stack of four QD layers 21, 31, 41 51. However, a stack of -15 layers can be achieved using the method according to the present invention, with 12 layers being an ideal number.
As is known, the emission wavelength of a QD structure is determined by the QD size and composition, which can be reduced by inter-diffusion during the capping procedure. By varying the As-precursor partial pressures during the cap growth, inter-diffusion and size reduction can be strongly reduced thus reducing the emission energy as well. Thus by using the method of the present invention to create the above described QD structures it is possible to produce a QD laser device which emits at wavelengths beyond 1.3 m.
The method used to realize the above QD structure will now be explained in detail. The QD structure 20 was grown on a (100) crystal structure GaAs substrate 27 by low-pressure Metal Organic Chemical Vapor Deposition (MOCVD) at 20 mbar. The QDs 24a, 24b, 24c, 24d, 24e were formed by depositing 4 monolayers (MLs) of InxGa(-x)As with a nominal In content of x = 0.5 at a growth temperature of 550 C and growth rate of 1 ML/s. The QDs, also know in the art as islands, were then covered by a 30 rim GaAs cap layer 22 and 24. The overgrowth was started after a growth interruption of 90 seconds under Arsine flow at the same growth temperature used for the QD layers. During the growth interruption and for the GaAs cap deposition the AsH3 partial pressure (PASH3) was run to run (samples A,B,C,D) varied between 1.4x10-' and 5. 7x10-' mbar. The QD layer was grown under identical growth condition for all the samples A, B. C, and D. Figure 3 shows the room temperature PL spectra of samples A, B. C and D, overgrown with rim of GaAs deposited with AsH3 partial pressure of 5.7x10-', 4.3x10-', 2.8x10-' and 1.4x10-' mbar, respectively. In the inset of figure 3 the ground state emission wavelength (Eo) as a function of the AsH3 partial pressure used in the capping procedure is plotted, together with the energy splitting AE o between the ground state emission and the first excited state. Clearly, the emission wavelength red shifts by decreasing the V/III ratio during the growth of the GaAs cap layer. The ground state peak position starts at 1260 rim (the typical peak position of prior art QDs grown on GaAs) for sample A, grown with the highest PASlI3, and increases nearly linearly up to 1330 rim in sample D, grown with the lowest PASH3. All spectra show the ground level (Eo) and the first (En) excited state transition of the QDs, as confirmed by the state filling dynamic obtained with increasing the excitation power (not shown). The energy splitting AE o is nearly constant in all samples, as shown in the inset of figure 3.
In figure 4 plots the full width half maximum (FWHM) measured for the spectra shown in figure 3 and the ratio between the low temperature (10 K) and room temperature radiative efficiency (TILT/ DIRT) as a function of the AsH3 partial pressure used in the capping procedure. The plot clearly shows that with increasing wavelength a systematic reduction of the emission spectral width occurs (from 35 meV for sample A down to 24 meV for sample D), demonstrating that the highest uniformity in the QD distribution is achieved in samples overgrown with lower AsH3 partial pressure, despite the QD layer itself being grown under identical growth conditions in all samples.
More importantly, a significant reduction in the temperature dependence of the integrated intensity is obtained by decreasing the V/III ratio: the quenching of the room temperature ground state emission goes from factor 9 in sample A, down to 3 in sample D, which represents the best result know result for QDs emitting at 1.3,um.
The strong red shift observed in the spectra can be justified only by an increased In content inside the QD and/or an increased island size, induced by the capping procedure.
Earlier studies carried out on MBE grown samples have shown important modifications of the island size, shape and density occurring during the morphological evolution of the QDs induced by the GaAs overgrowth surface reconstruction. The surface reconstruction strongly depends on the group III adatom surface mobility that, in turn, is controlled by the growth condition (primarily by the V/III ratio). Due to the complex surface structure resulting from the growth of the InGaAs QD layer, an important variation of the local GaAs growth rate is expected to occur during the capping procedure. Change in the GaAs local growth rate arises also from variations of the strain field associated to the In distribution inside and around the QDs. For a long enough surface diffusion length of the Ga adatoms (as obtained by employing low V/III ratio) the GaAs will grow only on the energetically favorable sites, i.e. on the wetting layer (100) surface and lower surface stress) and around the edge of the island. Overgrowth on the topmost QD surface, which is the most unfavorable growth site for GaAs, will begin only at a later stage of the growth. The delayed GaAs growth on the top of the island prevents the size reduction of the QDs, as found in the overgrowth of the MBE samples. On the other hand, in samples overgrown with high V/III ratio, the reduced surface diffusion length of Ga adatoms strongly reduces the local growth rate differences, thus allowing the GaAs growth directly on the top of the QD. The earlier island coverage enhances the In-Ga intermixing reducing both the size and the In mole fraction of the dot, with a consequent increase of the ground state emission energy of the samples. As a result, two effects should be invoked to explain the unexpected behavior found by changing the V/III ratio in the cap layer growth: i) In-Ga intermixing at the dot-barrier interface, and ii) island size variation. A reduced In- Ga intermixing should lead to a decrease of the FWHM of the optical emission, due to the better compositional uniformity of the dot ensemble, and to a reduced thermal escape (thus increased RT efficiency), due to QDs/barrier sharper interface and consequent deeper confining potential. Both effects are indeed clearly observed in figure 4.
It is important to note that know theoretical calculations show that the intermixing alone cannot explain the red shift observed experimentally. Instead, small variations of the dot volume (about 25%) around the value estimated by AFM measurements, would induce the observed shift of the wavelength of about 70 nm. Moreover, the theoretical calculations show that an increase of the dot height induces a decrease of the energy separation, AK' o, whereas an increase of the dot radius results in an increase of AK' o. As a consequence, the constant value of AE o, observed experimentally (see inset of figure 3), indicates that, even though both the dimension of the QDs are affected by the morphological evolution during the capping of the islands, the effects due to the variation of the radius and height are approximately compensated.
Thus the QD structure according to the present invention produced an emission beyond 1.3 microns from MOCVD grown InGaAs QDs embedded in GaAs matrix. Significant red shift of the emission wavelength and narrowing of the FWHM are obtained by reducing the V/III ratio for the growth of the GaAs cap layer. Most importantly, an improved value of 3 for the ratio between the low and room temperature radiative efficiency can be measured. These results are explained in term of modification in the morphological evolution and surface reconstruction undergone by the InGaAs islands during the growth of the GaAs cap.
Claims (13)
- I A quantum dot structure comprising a first GaAs layer having embedded therein a plurality of quantum dots, and a further GaAs layer disposed thereon, wherein said further layer is grown with a reduced partial pressure of AsH3.
- 2 A quantum dot structure as claimed in Claim 1, further comprising a GaAs substrate layer.
- 3 A quantum dot structure as claimed in Claim 2, wherein said GaAs substrate layer is n type.
- 4 A quantum dot structure as claimed in any preceding Claim, wherein the quantum dots are In(Ga)As.
- A laser device comprising a plurality of stacked quantum dot structures as claimed in any preceding Claim.
- 6 A laser device comprising 10 to 15 stacked quantum dot structures as claimed in any of preceding Claims 1-5.
- 7 A laser device comprising 12 stacked quantum dot structures as claimed in any of preceding Claims 1-5.
- 8 A laser device as claimed in Claims 5-7, wherein the device emits at a wavelength greater than 1.3 microns.
- 9 A method for making a quantum dot structure comprising the steps of: growing a first layer of GaAs growing a plurality of quantum dots in said first layer, growing a further layer of GaAs proximate over said quantum dots, wherein partial pressure is altered during the growth of said further layer.
- A method as claimed in Claim 9, wherein the growth steps are done by MOCVD.
- l l A method is claimed in any of preceding Claims 9-10, wherein the quantum dots are deposited in monolayers of In(Ga)As.
- 12 A method as claimed in any of preceding Claims 9-l l, wherein the partial pressure of AsH3 is varied from 5.7xlO- 1 mbar to 1.4xlO- 1 mbar.
- 13 A method as claimed in any of preceding Claims 9-11, wherein said step of varying said partial pressure alters the characteristics of the GaAs layers.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB0329610A GB2409334A (en) | 2003-12-20 | 2003-12-20 | Quantum dot structure having GaAs layers formed at varying partial pressures |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB0329610A GB2409334A (en) | 2003-12-20 | 2003-12-20 | Quantum dot structure having GaAs layers formed at varying partial pressures |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB0329610D0 GB0329610D0 (en) | 2004-01-28 |
| GB2409334A true GB2409334A (en) | 2005-06-22 |
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| Application Number | Title | Priority Date | Filing Date |
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| GB0329610A Withdrawn GB2409334A (en) | 2003-12-20 | 2003-12-20 | Quantum dot structure having GaAs layers formed at varying partial pressures |
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| Country | Link |
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| GB (1) | GB2409334A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103325663A (en) * | 2012-03-23 | 2013-09-25 | 北京邮电大学 | Preparation method of composite nanofiltration heterostructure capable of generating quantum dots on side wall of nanowire |
| US8835965B2 (en) | 2012-01-18 | 2014-09-16 | The Penn State Research Foundation | Application of semiconductor quantum dot phosphors in nanopillar light emitting diodes |
| US20220158415A1 (en) * | 2020-11-13 | 2022-05-19 | Denso Corporation | Semiconductor laser device |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5817538A (en) * | 1994-09-16 | 1998-10-06 | Fujitsu Limited | Method of making quantum box semiconductor device |
| US6177684B1 (en) * | 1998-03-17 | 2001-01-23 | Fujitsu Limited | Quantum semiconductor device having a quantum dot structure |
| US6235547B1 (en) * | 1994-04-28 | 2001-05-22 | Fujitsu Limited | Semiconductor device and method of fabricating the same |
| US20020168835A1 (en) * | 2001-03-26 | 2002-11-14 | Korea Institute Of Science Of Technology | Method of formation for quantum dots array using tilted substrate |
| GB2388957A (en) * | 2002-05-24 | 2003-11-26 | Imp College Innovations Ltd | Quantum dots for extended wavelength operation |
-
2003
- 2003-12-20 GB GB0329610A patent/GB2409334A/en not_active Withdrawn
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6235547B1 (en) * | 1994-04-28 | 2001-05-22 | Fujitsu Limited | Semiconductor device and method of fabricating the same |
| US5817538A (en) * | 1994-09-16 | 1998-10-06 | Fujitsu Limited | Method of making quantum box semiconductor device |
| US6177684B1 (en) * | 1998-03-17 | 2001-01-23 | Fujitsu Limited | Quantum semiconductor device having a quantum dot structure |
| US20020168835A1 (en) * | 2001-03-26 | 2002-11-14 | Korea Institute Of Science Of Technology | Method of formation for quantum dots array using tilted substrate |
| GB2388957A (en) * | 2002-05-24 | 2003-11-26 | Imp College Innovations Ltd | Quantum dots for extended wavelength operation |
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| Title |
|---|
| 11th Biennial (US) Workshop on Organometallic Vapour Phase Epitaxy, Keystone, CO, USA, 20-24 July 2003. Journal of Crystal Growth vol. 261, January 2004 (Amsterdam), J G Cederberg et al, "The impact of growth parameters on the formation of InAs quantum dots on GaAs(100) by MOCVD", pages 197-203. * |
| Journal of Crystal Growth vol. 170, 1997 (Amsterdam), K Kumakura et al, "Formation and charaterization of coupled quantum dots (CQDs) by selective area metalorganic vapor phase epitaxy", pages 700-704. * |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8835965B2 (en) | 2012-01-18 | 2014-09-16 | The Penn State Research Foundation | Application of semiconductor quantum dot phosphors in nanopillar light emitting diodes |
| CN103325663A (en) * | 2012-03-23 | 2013-09-25 | 北京邮电大学 | Preparation method of composite nanofiltration heterostructure capable of generating quantum dots on side wall of nanowire |
| CN103325663B (en) * | 2012-03-23 | 2016-03-16 | 北京邮电大学 | The preparation method of heterostructure is received in the compound of nanowire sidewalls growth quantum point |
| US20220158415A1 (en) * | 2020-11-13 | 2022-05-19 | Denso Corporation | Semiconductor laser device |
| US11764546B2 (en) * | 2020-11-13 | 2023-09-19 | Denso Corporation | Semiconductor laser device |
Also Published As
| Publication number | Publication date |
|---|---|
| GB0329610D0 (en) | 2004-01-28 |
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