GB2589356A - Van der Waals heterostructures - Google Patents
Van der Waals heterostructures Download PDFInfo
- Publication number
- GB2589356A GB2589356A GB1917317.8A GB201917317A GB2589356A GB 2589356 A GB2589356 A GB 2589356A GB 201917317 A GB201917317 A GB 201917317A GB 2589356 A GB2589356 A GB 2589356A
- Authority
- GB
- United Kingdom
- Prior art keywords
- substrate
- layer
- abrasion
- head
- rubbing
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
- 239000000463 material Substances 0.000 claims abstract description 60
- 239000000758 substrate Substances 0.000 claims abstract description 52
- 238000000034 method Methods 0.000 claims abstract description 38
- 238000005299 abrasion Methods 0.000 claims abstract description 22
- 239000003054 catalyst Substances 0.000 claims abstract description 10
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 claims abstract description 8
- 239000003990 capacitor Substances 0.000 claims abstract description 8
- 239000001257 hydrogen Substances 0.000 claims abstract description 8
- 229910052739 hydrogen Inorganic materials 0.000 claims abstract description 8
- 238000004519 manufacturing process Methods 0.000 claims abstract description 8
- 238000003825 pressing Methods 0.000 claims description 2
- 238000012546 transfer Methods 0.000 abstract description 4
- 239000010408 film Substances 0.000 description 46
- 239000010410 layer Substances 0.000 description 36
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 18
- 230000004044 response Effects 0.000 description 15
- 229910021389 graphene Inorganic materials 0.000 description 14
- 230000003287 optical effect Effects 0.000 description 11
- 230000000694 effects Effects 0.000 description 10
- 230000005284 excitation Effects 0.000 description 10
- 239000010931 gold Substances 0.000 description 10
- 230000005855 radiation Effects 0.000 description 10
- 239000002159 nanocrystal Substances 0.000 description 8
- 239000000523 sample Substances 0.000 description 7
- 238000005259 measurement Methods 0.000 description 6
- 230000008569 process Effects 0.000 description 6
- 239000010409 thin film Substances 0.000 description 6
- 238000006243 chemical reaction Methods 0.000 description 5
- 229910052961 molybdenite Inorganic materials 0.000 description 5
- 229910052982 molybdenum disulfide Inorganic materials 0.000 description 5
- 239000000843 powder Substances 0.000 description 5
- 230000003595 spectral effect Effects 0.000 description 5
- 230000002123 temporal effect Effects 0.000 description 5
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 5
- 230000015572 biosynthetic process Effects 0.000 description 4
- 239000013078 crystal Substances 0.000 description 4
- 239000004205 dimethyl polysiloxane Substances 0.000 description 4
- 239000006185 dispersion Substances 0.000 description 4
- 238000005516 engineering process Methods 0.000 description 4
- 239000007791 liquid phase Substances 0.000 description 4
- CWQXQMHSOZUFJS-UHFFFAOYSA-N molybdenum disulfide Chemical compound S=[Mo]=S CWQXQMHSOZUFJS-UHFFFAOYSA-N 0.000 description 4
- 229920000435 poly(dimethylsiloxane) Polymers 0.000 description 4
- 238000000411 transmission spectrum Methods 0.000 description 4
- 239000003082 abrasive agent Substances 0.000 description 3
- 230000004888 barrier function Effects 0.000 description 3
- 229910052681 coesite Inorganic materials 0.000 description 3
- 229910052906 cristobalite Inorganic materials 0.000 description 3
- 229910002804 graphite Inorganic materials 0.000 description 3
- 239000010439 graphite Substances 0.000 description 3
- 238000005286 illumination Methods 0.000 description 3
- 238000004502 linear sweep voltammetry Methods 0.000 description 3
- 230000010287 polarization Effects 0.000 description 3
- 230000002441 reversible effect Effects 0.000 description 3
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N silicon dioxide Inorganic materials O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 3
- 239000002904 solvent Substances 0.000 description 3
- 229910052682 stishovite Inorganic materials 0.000 description 3
- 229910052905 tridymite Inorganic materials 0.000 description 3
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 2
- XOJVVFBFDXDTEG-UHFFFAOYSA-N Norphytane Natural products CC(C)CCCC(C)CCCC(C)CCCC(C)C XOJVVFBFDXDTEG-UHFFFAOYSA-N 0.000 description 2
- 238000001069 Raman spectroscopy Methods 0.000 description 2
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 2
- 238000010521 absorption reaction Methods 0.000 description 2
- 239000002390 adhesive tape Substances 0.000 description 2
- ROOXNKNUYICQNP-UHFFFAOYSA-N ammonium persulfate Chemical compound [NH4+].[NH4+].[O-]S(=O)(=O)OOS([O-])(=O)=O ROOXNKNUYICQNP-UHFFFAOYSA-N 0.000 description 2
- 229910003481 amorphous carbon Inorganic materials 0.000 description 2
- 238000013459 approach Methods 0.000 description 2
- 238000005452 bending Methods 0.000 description 2
- 238000012512 characterization method Methods 0.000 description 2
- 238000000576 coating method Methods 0.000 description 2
- 150000001875 compounds Chemical class 0.000 description 2
- 229910052802 copper Inorganic materials 0.000 description 2
- 239000010949 copper Substances 0.000 description 2
- 238000000151 deposition Methods 0.000 description 2
- 230000008021 deposition Effects 0.000 description 2
- 238000001514 detection method Methods 0.000 description 2
- 239000003989 dielectric material Substances 0.000 description 2
- 239000010411 electrocatalyst Substances 0.000 description 2
- 239000003792 electrolyte Substances 0.000 description 2
- 238000004299 exfoliation Methods 0.000 description 2
- 239000000835 fiber Substances 0.000 description 2
- 230000006870 function Effects 0.000 description 2
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 description 2
- 229910052737 gold Inorganic materials 0.000 description 2
- 229910052736 halogen Inorganic materials 0.000 description 2
- 150000002367 halogens Chemical class 0.000 description 2
- 230000006872 improvement Effects 0.000 description 2
- 238000007641 inkjet printing Methods 0.000 description 2
- 230000003993 interaction Effects 0.000 description 2
- 230000003647 oxidation Effects 0.000 description 2
- 238000007254 oxidation reaction Methods 0.000 description 2
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 2
- 238000010248 power generation Methods 0.000 description 2
- 230000002035 prolonged effect Effects 0.000 description 2
- 230000009467 reduction Effects 0.000 description 2
- 239000004065 semiconductor Substances 0.000 description 2
- 239000000243 solution Substances 0.000 description 2
- 235000011149 sulphuric acid Nutrition 0.000 description 2
- 238000003786 synthesis reaction Methods 0.000 description 2
- -1 Polydimethylsiloxane Polymers 0.000 description 1
- 229910008062 Si-SiO2 Inorganic materials 0.000 description 1
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 1
- 229910006403 Si—SiO2 Inorganic materials 0.000 description 1
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 1
- 239000005864 Sulphur Substances 0.000 description 1
- 230000004075 alteration Effects 0.000 description 1
- 239000005030 aluminium foil Substances 0.000 description 1
- 229910001870 ammonium persulfate Inorganic materials 0.000 description 1
- 239000007864 aqueous solution Substances 0.000 description 1
- 238000004630 atomic force microscopy Methods 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 239000011230 binding agent Substances 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 239000000969 carrier Substances 0.000 description 1
- 230000015556 catabolic process Effects 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 238000005229 chemical vapour deposition Methods 0.000 description 1
- 230000002860 competitive effect Effects 0.000 description 1
- 238000011109 contamination Methods 0.000 description 1
- 238000006731 degradation reaction Methods 0.000 description 1
- 239000008367 deionised water Substances 0.000 description 1
- 229910021641 deionized water Inorganic materials 0.000 description 1
- 238000005137 deposition process Methods 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- ZOMNIUBKTOKEHS-UHFFFAOYSA-L dimercury dichloride Chemical class Cl[Hg][Hg]Cl ZOMNIUBKTOKEHS-UHFFFAOYSA-L 0.000 description 1
- 238000002848 electrochemical method Methods 0.000 description 1
- 238000005530 etching Methods 0.000 description 1
- 230000008020 evaporation Effects 0.000 description 1
- 238000001704 evaporation Methods 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 230000005251 gamma ray Effects 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 238000001566 impedance spectroscopy Methods 0.000 description 1
- 238000001453 impedance spectrum Methods 0.000 description 1
- 230000002427 irreversible effect Effects 0.000 description 1
- 239000013081 microcrystal Substances 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012544 monitoring process Methods 0.000 description 1
- 239000002105 nanoparticle Substances 0.000 description 1
- 230000005693 optoelectronics Effects 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 230000036961 partial effect Effects 0.000 description 1
- 229920003229 poly(methyl methacrylate) Polymers 0.000 description 1
- 229920000642 polymer Polymers 0.000 description 1
- 239000004926 polymethyl methacrylate Substances 0.000 description 1
- 230000002829 reductive effect Effects 0.000 description 1
- 238000010079 rubber tapping Methods 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 229910052710 silicon Inorganic materials 0.000 description 1
- 239000010703 silicon Substances 0.000 description 1
- 239000002356 single layer Substances 0.000 description 1
- 238000004528 spin coating Methods 0.000 description 1
- 229910001220 stainless steel Inorganic materials 0.000 description 1
- 239000010935 stainless steel Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- XCUPBHGRVHYPQC-UHFFFAOYSA-N sulfanylidenetungsten Chemical compound [W]=S XCUPBHGRVHYPQC-UHFFFAOYSA-N 0.000 description 1
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 description 1
- 229910052721 tungsten Inorganic materials 0.000 description 1
- 239000010937 tungsten Substances 0.000 description 1
- 238000002525 ultrasonication Methods 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/02104—Forming layers
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/02002—Preparing wafers
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B82—NANOTECHNOLOGY
- B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
- B82Y40/00—Manufacture or treatment of nanostructures
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B32/00—Carbon; Compounds thereof
- C01B32/15—Nano-sized carbon materials
- C01B32/182—Graphene
- C01B32/184—Preparation
- C01B32/19—Preparation by exfoliation
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
- C25B1/00—Electrolytic production of inorganic compounds or non-metals
- C25B1/01—Products
- C25B1/02—Hydrogen or oxygen
- C25B1/04—Hydrogen or oxygen by electrolysis of water
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
- C25B1/00—Electrolytic production of inorganic compounds or non-metals
- C25B1/50—Processes
- C25B1/55—Photoelectrolysis
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
- C25B11/00—Electrodes; Manufacture thereof not otherwise provided for
- C25B11/04—Electrodes; Manufacture thereof not otherwise provided for characterised by the material
- C25B11/051—Electrodes formed of electrocatalysts on a substrate or carrier
- C25B11/052—Electrodes comprising one or more electrocatalytic coatings on a substrate
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
- C25B11/00—Electrodes; Manufacture thereof not otherwise provided for
- C25B11/04—Electrodes; Manufacture thereof not otherwise provided for characterised by the material
- C25B11/051—Electrodes formed of electrocatalysts on a substrate or carrier
- C25B11/055—Electrodes formed of electrocatalysts on a substrate or carrier characterised by the substrate or carrier material
- C25B11/057—Electrodes formed of electrocatalysts on a substrate or carrier characterised by the substrate or carrier material consisting of a single element or compound
- C25B11/061—Metal or alloy
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
- C25B11/00—Electrodes; Manufacture thereof not otherwise provided for
- C25B11/04—Electrodes; Manufacture thereof not otherwise provided for characterised by the material
- C25B11/051—Electrodes formed of electrocatalysts on a substrate or carrier
- C25B11/073—Electrodes formed of electrocatalysts on a substrate or carrier characterised by the electrocatalyst material
- C25B11/075—Electrodes formed of electrocatalysts on a substrate or carrier characterised by the electrocatalyst material consisting of a single catalytic element or catalytic compound
- C25B11/077—Electrodes formed of electrocatalysts on a substrate or carrier characterised by the electrocatalyst material consisting of a single catalytic element or catalytic compound the compound being a non-noble metal oxide
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
- C25B11/00—Electrodes; Manufacture thereof not otherwise provided for
- C25B11/04—Electrodes; Manufacture thereof not otherwise provided for characterised by the material
- C25B11/051—Electrodes formed of electrocatalysts on a substrate or carrier
- C25B11/073—Electrodes formed of electrocatalysts on a substrate or carrier characterised by the electrocatalyst material
- C25B11/075—Electrodes formed of electrocatalysts on a substrate or carrier characterised by the electrocatalyst material consisting of a single catalytic element or catalytic compound
- C25B11/087—Photocatalytic compound
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
- H01L31/08—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof in which radiation controls flow of current through the device, e.g. photoresistors
- H01L31/085—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof in which radiation controls flow of current through the device, e.g. photoresistors the device being sensitive to very short wavelength, e.g. X-ray, Gamma-rays
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
- H01L31/18—Processes or apparatus specially adapted for the manufacture or treatment of these devices or of parts thereof
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02N—ELECTRIC MACHINES NOT OTHERWISE PROVIDED FOR
- H02N1/00—Electrostatic generators or motors using a solid moving electrostatic charge carrier
- H02N1/04—Friction generators
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L29/00—Semiconductor devices specially adapted for rectifying, amplifying, oscillating or switching and having potential barriers; Capacitors or resistors having potential barriers, e.g. a PN-junction depletion layer or carrier concentration layer; Details of semiconductor bodies or of electrodes thereof ; Multistep manufacturing processes therefor
- H01L29/02—Semiconductor bodies ; Multistep manufacturing processes therefor
- H01L29/12—Semiconductor bodies ; Multistep manufacturing processes therefor characterised by the materials of which they are formed
- H01L29/16—Semiconductor bodies ; Multistep manufacturing processes therefor characterised by the materials of which they are formed including, apart from doping materials or other impurities, only elements of Group IV of the Periodic Table
- H01L29/1606—Graphene
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L29/00—Semiconductor devices specially adapted for rectifying, amplifying, oscillating or switching and having potential barriers; Capacitors or resistors having potential barriers, e.g. a PN-junction depletion layer or carrier concentration layer; Details of semiconductor bodies or of electrodes thereof ; Multistep manufacturing processes therefor
- H01L29/02—Semiconductor bodies ; Multistep manufacturing processes therefor
- H01L29/12—Semiconductor bodies ; Multistep manufacturing processes therefor characterised by the materials of which they are formed
- H01L29/24—Semiconductor bodies ; Multistep manufacturing processes therefor characterised by the materials of which they are formed including, apart from doping materials or other impurities, only semiconductor materials not provided for in groups H01L29/16, H01L29/18, H01L29/20, H01L29/22
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/30—Hydrogen technology
- Y02E60/36—Hydrogen production from non-carbon containing sources, e.g. by water electrolysis
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Organic Chemistry (AREA)
- Materials Engineering (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- Metallurgy (AREA)
- Condensed Matter Physics & Semiconductors (AREA)
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Manufacturing & Machinery (AREA)
- Computer Hardware Design (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Power Engineering (AREA)
- Inorganic Chemistry (AREA)
- Nanotechnology (AREA)
- Electromagnetism (AREA)
- Crystallography & Structural Chemistry (AREA)
- Photovoltaic Devices (AREA)
- Carbon And Carbon Compounds (AREA)
Abstract
A method suitable for use in the fabrication of a van der Waals heterostructure, the method comprises the steps of applying a mask 16 to a substrate 14, rubbing a first material 12 against the substrate 14 to deposit and apply, by abrasion, a first layer of the first material to the substrate 14, applying a second mask over the first layer, and rubbing a second material against the substrate 14 to apply, by abrasion, a second layer of the second material over at least part of the first layer. The second material may be less hard or less abrasive than the first material 12. The first and second materials may be applied using a rotatable head 10. A further step may include the transfer of a prefabricated element which may comprise a layer formed by CVD. A multi-layered structure formed using this method is specified, where the structure may further comprise a photo detector, a light emitting device, a transistor, a capacitor, a resistor, a superconducting memory device, a single photon emitter located on a film, a triboelectric generator or a hydrogen evolution catalyst.
Description
VAN DER WAALS HETEROSTRUCTURES
This invention relates to the fabrication of Van der Waals (vdW) heterostructures.
High quality vdW heterostructures offer many improvements over conventional materials as they are lightweight, transparent and are compatible with flexible substrates whilst at the same time display competitive performance to that of conventional compound semiconductor electronics. The highest quality heterostructures are fabricated through mechanical exfoliation of bulk single crystals and built up layer-by-layer using standard mechanical transfer procedures.
This method, however, is not scalable.
Chemical vapour deposition techniques, where monolayer films are grown layer by layer at high temperatures have shown promising results. However, the energy cost of growth is high for a given quantity of material, the growth of multi-layer heterostructures is complex and is also confined to a small number of material combinations. Furthermore, transfer of the films formed in this manner from catalyst substrates often introduces contamination, tears and/or cracks which may prevent the formation of high quality vertical heterostructure devices.
An alternative approach for use in the mass-scalable production of nanocrystal heterostructures is through the ink-jet printing of liquid-phase exfoliated dispersions. In this technique, 2D dispersions are produced through either ultra-sonication or shear force exfoliation of bulk vdW microcrystals in suitable solvents. This leads to stable dispersions which can then subsequently be printed on a variety of substrates. By mixing the dispersions with specialist binders the heterostructures can also be built-up layer-by-layer through ink-jet printing. However, strong disorder in the crystals caused by both solvent induced oxidation and poor interface quality can lead to severe performance degradation compared to devices based on single crystals. Furthermore, the production method is unlikely to be incompatible with many highly air sensitive vdW materials, and so the range of suitable materials with which the technique can be used is limited. Moreover, residue solvent in the printed films are also likely to degrade the electrical properties of the devices by reducing the quality of the interface between neighbouring nanocrystals.
It is an object of the invention to provide a technique that allows the building up of a semi-transparent and flexible vdW nanocrystal heterostructure in a simple and convenient manner, using a wide range of materials.
According to a first aspect of the invention there is provided a method for use in the fabrication of a van der Waals heterostructure, the method comprising the steps of applying a mask to a substrate, rubbing a first material against the substrate to deposit and apply, by abrasion, a first layer of the first material to the substrate, applying a second mask over the first layer, and rubbing a second material against the substrate to apply, by abrasion, a second layer of the second material over at least part of the first layer.
It will be appreciated that, in this manner, a multi-layered vdW heterostructure may be formed upon the substrate.
The second material is preferably less hard or less abrasive than the first material. In this manner, the risk of damaging the first layer during the application of the second layer is reduced.
The steps of rubbing the first and second materials against the substrate are preferably achieved using a rotatable head. By way of example, the material to be deposited may be applied to the rotatable head or to the substrate, and the material may be deposited onto the substrate by pressing the head against the substrate whilst rotating the head, and moving the head relative to the substrate to apply the material over an area of the substrate, thereby applying a layer of the material to the substrate.
Further layers may be applied using this technique.
As mentioned above, the second layer is preferably of a different material to the first layer. By way of example, it may be of a less abrasive material than the material of the first layer. If there is a need to apply a layer of a harder or more abrasive material onto a layer of a softer or less abrasive material, then this may be achieved by transfer of a preformed layer onto the substrate. Rather than comprise a single preformed layer, a multi-layered element could be transferred in this manner.
According to another aspect of the invention there is provided a multi-layered structure fabricated using the afore described method. The structure may comprise, for example, a photo detector or light emitting device. Alternatively, it could comprise a transistor, a capacitor or a resistor. It is further envisaged that the structure could take the form of a superconducting memory device. The method may be used to introduce single photon emitters onto a film. Other applications in which the invention may be employed include in the formation of triboelectric generators and hydrogen evolution catalysts.
The invention will further be described, by way of example, with reference to the accompanying drawings, in which: Figure 1A illustrates steps the fabrication of a thin film produced through powder abrasion of vdW powders for the production heterostructures through mechanical abrasion; Figure 1B illustrates typical optical transmission spectra for different materials deposited onto 0.5 mm thick PET substrates; Figure 2 illustrates the electronic properties of the bare films with (A) showing Isd-Vsd of a graphitic film produced through mechanical abrasion (inset: optical photograph of a graphitic film produced on a 2.5 cm PET substrate thinned to three different thicknesses by back-peeling with adhesive tape); (B) showing gate dependence of the channel resistivity for the device shown in the bottom-right inset using an liC103 electrolyte. Top left inset: Contour map of the Isd-Vsd for different applied gate voltages; (C) showing typical Isd-Vsd for a 5 mm x 0.025 mm two terminal device based on MoS2 powder abrasion with an average film thickness of 100 nm for different levels of applied uniaxial strain (inset: Vsa is held at 0.5V and the device is subjected to reversible uniaxial strain in time); and (D) showing impedance spectroscopy for a hBN dielectric capacitor produced using a Smm thick hBN film; Figure 3 illustrates mechanically abraded films for photodetection applications with (A) showing Isd-Vsd for a planer geometry W52 channel without (black curve) and with (red curve) 111 mW/cm2 incoherent optical excitation; (B) showing Isd-Vsd with and without optical excitation for a vertical WS2 device with a candle flame deposited amorphous carbon top electrode; (C) showing similar vertical heterostructure as in (B) but with a CVD graphene top electrode with device area of 1mm x lmm and thickness of 300nm (inset: a zoomed in region around Vsd=+/-1V with and without optical excitation and with power density of 74 mW/cm2); and (D) showing spectral responsivity of the diode structure shown in (C) (inset: temporal dependence of the photocurrent when opening and closing the shutter on the incident white light of power 74mW/cm2 and Vsd=-1 V); Figure 4 illustrates heterostructures produced solely from mechanical abrasion of 2D powders with (A) showing photoresponse of a diode structure consisting of Gr-W52-Gr (inset: Temporal response of the open circuit photovoltage); and (B) showing multi-layer type-II band alignment diode consisting of Gr-W52-Mo52-Gr in dark and under optical excitation of 100mW/cm2 (Device area 2 x 3 mm); Figure 5 illustrates W52 films as a catalyst for hydrogen evolution and photocurrent generation with (A) showing photocurrent power generation for increasing resistive load (inset: temporal response of the generated photocurrent measured through a 11V1Ohm resistor); (B) showing spectral dependence of the responsivity of the generated photocurrent; (C) showing polarization curves measured in 0.5 M H2504 with a scan rate of 2mV/s at room temperature (inset: shows the onset HER potential of W52; and (D) showing linear portions of the Tafel plots for W52 sample exfoliated by mechanical abrasion on an Au thin film; Figure 6 illustrates High Energy Radiation detection with (A) showing the response of the current through the device for a high 30Gy gamma radiation dose; and (B) showing the temporal response of the conductivity for 5 successive exposures to 5Gy's; and Figure 7 illustrates a triboelectric nanogenerator based on abraded films with (A) showing a schematic of the device and electrical setup; and (B) showing the time response for three successive release cycles.
Referring to the accompanying drawings, Figure 1A shows the general approach used in accordance with an embodiment of the invention to produce thin films of 20 nanocrystals on Si02 and flexible PET substrates. As illustrated, a soft polymer, Polydimethylsiloxane (PDMS) rotatable writing pad 10 is coated in a 2D material powder film 12. The PDMS pad 10 is then oscillated back and forth against a substrate 14, whilst being pressed against the substrate and whilst the writing pad 10 is being rotated, with various 2D materials embedded or located between the writing pad 10 and the substrate 14 to cause the build-up of a layer of material upon the substrate 14.
To ensure that the 2D material is only written at selected locations on the substrate 14, a tape mask 16 is applied to the substrate 14 before writing. After the material has been written or deposited in this manner, the tape mask 16 is removed leaving only the unmasked region coated in the 2D material. These steps are illustrated diagrammatically in Figure 1A, steps 1 to 3. As shown in step 4 of Figure 1A, this process can then be repeated to build up multi-layered heterostructures such as capacitors or photovoltaics as described below. By way of example, by using a different tape mask 16 leaving different unmasked regions, heterostructures of relatively complex form may be built up.
In order to avoid damage to a layer that has already been deposited, subsequent layers are preferably of materials that are softer or are less abrasive that the layer(s) already deposited.
The films deposited or fabricated using the technique described hereinbefore can be studied using Raman spectroscopy and atomic force microscopy. Figure 1B shows the optical transmission spectra of several different 20 materials fabricated by mechanical abrasion on a 0.5 mm thick PET substrate, the resultant films displaying some level of transparency which can also be tuned to higher levels by back peeling the films with an adhesive tape. Examples of the transmission spectra of various films are also shown in Figure 1B and show the characteristic increases in absorption associated with the A and B excitons indicating that the films still display similar optical properties compared to the bulk pristine materials.
Devices fabricated by mechanical abrasion in this manner may have a CVD graphene layer applied thereto, for example by spin coating PMMA onto CVD graphene deposited onto copper, applying a tape window thereto and etching away the copper from selected parts thereof using a 0.1 M aqueous solution of ammonium persulfate, for example over a period of around 6 hrs.
The CVD graphene may then be transferred onto the target device completing the heterostructure. To finish the device, it may be baked for 1hr at 150 degrees to improve the mechanical contact of the CVD graphene with the abraded nano-crystal films. It will be appreciated that in this manner, a harder or more abrasive layer can be applied to an already deposited layer. The method thus allows relatively greater flexibility of design, and so allows heterostructures for use in a wide range of applications to be fabricated.
Materials characterisation Raman spectroscopy was carried out using 532 nm excitation at 1 mW laser power focused onto a 1 mm spot. AFM was performed using a Bruker lnnova system operating in the tapping mode to ensure minimal damage to the sample's surface. The tips used were Nanosensors PPP-NCHR, which have a radius of curvature smaller than 10 nm and operate in a nominal frequency of 330 kHz.
Optical measurements Optical transmission spectra were recorded using an Andor Shamrock 500i spectrograph with 300I/mm grating resolution and iDus 420 CCD. A fibre coupled halogen white light source was used to excite the photo-active samples which generates 1.4W at the fibre tip. The white light is collimated to give uniform excitation of 70-100 mW/cm2. The white light source was blocked for the time response using a mechanical shutter with a response time of 10 ms. The spectral dependence of the photocurrent was carried out using 10nm band pass filters to filter the halogen white light source with the power at each wavelength calibrated using a Thorlabs photodiode 5120C.
Electrical measurements Electron transport measurements were carried out using a KE2400 source-meter for both source and gate electrodes. An Agilent 34410A multi meter was used to record the voltage drop over a variable resistor in order to determine the drain current and also photo response for different load resistances.
Electrochemical data was obtained using an Ivium-stat potentiostat/galvanostat. Linear sweep voltammetry (LSV) experiments were carryout in 0.5 M H2SO4 with a scan rate of 2 mV/s. For determination of activity of hydrogen evolution reaction (HER), a three-electrode electrochemical cell was used, i.e., saturated calomel electrode (SCE) (reference), platinum foil electrode (counter), and WS2/Au (working). The work electrode area used was 0.196 cm2 (Figure 1). The reference electrode was stored in KCl solution and rinsed with deionized water before use. For the measurements, high-purity N2 gas was bubbled into the solution for at least 60 min before the electrochemical measurements. The potentials reported here are with respect to reversible hydrogen electrode (E (RHE) = E (SCE) + 0.273 V [refs].) In many applications, the electronic performance of the films is important. Figure 2 highlights some basic electrical characterisation measurements of the materials. Figure 2A displays an IsdVsd curve for a thin graphite film with transparency of 20% which gives a characteristic resistance per square of 2 KOhm, similar to levels achieved with structures fabricated using other techniques. Importantly, the thickness of the film can be controlled by thinning with specialist tapes, allowing for improved transparency but increased resistance.
It has been found that the resistance of the few layer graphitic channel can be controlled by application of a gate-voltage (indicating <10 layer individual crystallite thicknesses). By way of example, an electrolyte gate Li*:C103-may be employed, drop cast over the channel region and contacted using an abraded graphitic gate electrode. Figure 2B shows the typical resistance vs gate voltage for a tape thinned graphitic channel region, with the inset showing a contour map of the Isd-Vsd for different applied gate voltages. It has been found that the electro-neutrality region is at large positive gate voltages, indicating a strong p-type doping, likely due to ambient water or oxygen doping. It should be noted that not all substrates are compatible with direct abrasion of graphite. Success was found with PET but not with Si02, but all other 2D materials explored were found to be compatible with Si02 substrates also. Figure 1C shows some typical Isd-Vsd curves for a MoS2 channel. The different curves are for increasing (red to blue) uniaxial strain generated by bending the 0.5mm PET substrate in a custom-built bending rig. It was found that the device resistance increased for increased levels of strain, and that the resistance changes are reversible as shown in the inset of Figure 2C, indicating that these films are suitable for strain sensing applications.
Important for any integrated electronic application is the development of capacitors. By making use of hBN dielectrics produced through mechanical abrasion over evaporated gold electrodes, films of thickness 5±11.1m (estimated from AFM and surface profile measurements) were produced. Following the deposition of the hBN dielectric, a sheet of CVD graphene was transferred onto the hBN film with two Au electrodes which act as the source and drain contacts for the graphene channel. An optical image of the device is shown in the inset of Figure 2D. The total area of the capacitor in this instance was approximately 2x10-6m2. The impedance spectrum is presented in Figure 2D and can be well described by the capacitive contribution, I Zr I = (2re f. The gradient to the linear fit, therefore, gives the capacitance which we find to be C=9.8pF. If we assume a plane plate capacitor model, then the capacitance is related to the relative permittivity by the following relation C = E.77/4a, which allows us to make an estimate of the dielectric constant, which we find to be 6,-2.8. The dielectric constants for typical nanocrystal hBN dielectrics vary wildly, with values ranging from 1.5 up to 200, whilst single crystal hBN is known to display a relative permittivity of -4. The lower value found in the material manufactured in accordance with the invention could be due to air voids in the films effectively lowering the effective capacitance of the whole barrier.
Photodetection and Photovoltaic Devices TMDC's are semiconductor materials with an indirect bandgap in the bulk and have already shown great promise for future flexible photovoltaic and photodetection applications. Heterostructures based on liquid phase exfoliated nanocrystals typically display poor photo detectivity in the order of 10-1004tA/W restricting their use in certain applications. Devices manufactured in accordance with the invention display a significant improvement in the photo-response of simple photodetector devices. Figure 3 shows a variety of different photodetection architectures, including lateral as well as vertical. The most basic focusses on simple in-plane channel of WS2 on Si-SiO2 substrates fabricated by mechanically abrading WS2nanocrystals over a 1cm substrate followed by shadow mask evaporation of Cr/Au electrodes using the technique described hereinbefore. This leaves a 25pm channel length with a channel width of 1mm and a typical film thickness of -1 pm. The 1"i-Vsd curves are shown in Figure 3A with (red curve) and without (black curve) excitation with an incoherent white light source with a power density of 111mW/cm2. The asymmetry in the Isd-Vsd curves is likely due to either asymmetric doping of the different regions of the abraded films or differences in the mechanical contact of the electrodes after deposition. Such simple planar photodetectors already show improved photo-responsivity compared with liquid phase exfoliated materials with responsivity up to 18mA/W at Vsd=-2V. A simple and quick route to construct vertical heterostructures is to deposit amorphous carbon top electrodes, deposited from a candle flame. To selectively deposit the material an aluminium foil shadow mask may be employed, but this may have the effect of strongly increasing the vertical junction resistance, likely explained by the partial oxidation of the WS2 film during the flame deposition process (expected as the WS2 film is being passed across a naked flame). The responsivity for those structures is still found to be -0.5mA/W, the reduction is likely explained because of the lower transparency of the thick highly absorbing a-C top electrode and degraded WS2 film.
By making use of a CVD graphene top electrode, chosen because of its high conductivity and transparency, the optoelectronic properties the abraded WS2 films can be addressed without using highly absorbing top electrodes. The Isd-Vsd curve of a typical device is shown in Figure 3C and shows a greater conductivity compared to the a-C device shown in Figure 3B. This is more representative of the true vertical conductivity of the pristine abraded WS2 films. Indeed, similar vertical devices based on n and p-type silicon show similar conductivities with CVD graphene top electrodes. The asymmetry in the Isd-Vsd curves here is down to the difference in the work functions of the graphene (4.6-4.9 eV) and Au (-5.2 eV) with the conduction band edge of the WS2 closely aligned with the neutrality point of graphene. This means that the conductivity is high at zero bias as electron transport occurs through the conduction band of the WS2 while at negative voltages the energy difference between the chemical potential of graphene and the conduction band of WS2 increases therefore increasing the barrier for conduction which is seen as a reduction in the conductivity. The spectral dependence of the photo responsivity for this device is plotted in Figure 3D with a peak responsivity at 2.0 eV consistent with the peak in absorption associated with the A-exciton, and maximal responsivities of 0.15 A/W at Vsd=-1V. The time response to the incident white light source is also shown in the inset with peak photocurrent values of 100pA at Vsd = -1V under uniform white light illumination of 74mW/cm2.
More complex vertical heterostructures may be fabricated by repeating steps (1-3) shown in Figure 1A with all the layers deposited through abrasion methods. Figure 4A shows the Isd-Vsd curves for a single vertical diode structure consisting of Gr-WS2-Gr in dark and under a white light exposure of 100mW/cm2. The top inset shows a photo of ten such diode structures connected in series on a 0.5mm PET substrate highlighting the up scalability of the technology, and the bottom inset shows the time response of the open circuit voltage for one representative junction. A more complex type-II band alignment heterostructure consisting of Gr-W52-Mo52-Gr is shown in Figure 4B, all layers of which are again deposited through the above described mechanical abrasion technique. The asymmetric Isd-Vsd (black curve) is likely a result of the band misalignment between the WS2 and MoS2 materials. Upon illumination the vertical conductivity increases significantly and exhibits a photo response of a few mA/W and an open circuit voltage of 14 mV and a short circuit current of 100 nA under 110 mW/cm-2 white light illumination. This leads to a power conversion efficiency of 10-5%. The low value likely due to the highly absorbing top graphene electrode and also the thick MoS2 layer, which was necessary to prevent short circuit, this means most of the light is absorbed before reaching the p-n junction and the charge separation is likely taking place at the Gr-MoS2 interface.
Hydrogen Evolution and Photocurrent Generation Mono and few layer TM DC's have been widely considered for their potential as electro catalysts for the hydrogen evolution reaction. Here, we select W52 as its the most thermoneutral, therefore minimizing the barrier for the photo-excited splitting of water. A useful bi product of the light assisted HER reaction is the generation of photocurrent. Figure 5A displays the photocurrent results for a 1 cm-2 WS2electro catalyst produced through mechanical abrasion on an Au substrate (we also demonstrate the large area compatibility with commercial stainless steel in the supplementary materials). Figure 5A shows the photocurrent power generation of a WS2 film abraded onto a thermally evaporated Au substrate and placed in DI water. The photocurrent is measured between a Pt wire in the DI water and the Au substrate for various resistive loads. The maximum power generated is found to reach 100 pW/cm2 at a load of 1 MOhm (comparable to the resistance of the cell). The inset to Figure 5A shows the time response of the photocurrent determined from the voltage drop over a 1MOhm resistor. To show that the photoresponse is due to WS2 film we also perform a spectral study of the short circuit photocurrent, Figure 5B.
We observe that there is a small peak at E-2 eV consistent with the direct exciton in WS2. The responsivity is then found to increase rapidly for higher excitation energy consistent with the increased joint density of states in WS2 at higher energies. Ultimately, we find peak values of mA/W at 400 nm excitation. The inset of Figure 5B displays the power dependence for 550 nm excitation, we observe that the responsivity saturates at very low powers (70 mW/cm2) and then drops rapidly to 1/3rd of the peak value at maximum power available.
The electrochemical performance of our WS2 films have been characterised 0.5 M H2SO4 via linear sweep voltammetry (LW). The HER polarization curves of the current density are plotted as a function of potential for a representative WS2 sample and shown in Figure 5C. We find a current density of 8.5 mA/cm2 at an overpotential of 200 mV, comparable to the values observed elsewhere. The inset of Figure 5C shows the onset potential of -97 mV (vs RH E). This shows that WS2 films produced through mechanical abrasion are suitable for HER catalyst applications. The overpotential is plotted in Figure 5D and the absolute value of the current density within a cathodic potential window and the corresponding Tafel fit is shown, red curve. Thus, the polarization curve shows an exponential behaviour, with the Tafel equation overpotential= a+b log lj (where b represents the Tafel slope) and j is the current density. The better the catalyst material gives the highest currents at the smallest overpotential. For our WS2 films we find a Tafel slope of 111 mV/dec, Figure 5D. The reported Tafel slopes vary significantly for different studies depending strongly on the synthesis route of the WS2 films. For example, Bonde et al. reported the HER activity on carbon supported WS2 nanoparticles with Tafel slopes of 135 mV/dec. Xiao et al. used an electrochemical route to obtain the amorphous tungsten sulphide thin films onto nonporous gold, which the Tafel slope was 74 mV/dec. Chen et al. found a similar value (78 mV/dec) for the WS2 prepared at 1000 C. However, the synthesis route of these works involves high temperature processes and/or several steps to obtain the W52 catalysts. While the WS2 catalysts exfoliated by mechanical abrasion are rapidly produced through a single low-cost step.
WS2 Based Ionising Radiation Detector High energy photon-matter interactions including, the photoelectric effect (PE), Rayleigh scattering (RS) and Compton scattering (CS) depend strongly of the atomic mass, Z. Specifically the cross-section of such processes depends on the atomic mass as Z as --24-5, Z2 and Z for the PE, RS and CS processes respectively.
High energy gamma-ray radiation detectors have practical uses in various sectors from medical to space exploration. Ideally, they should be highly sensitive while being radiation hard (That is the response should not change greatly after prolonged exposure). The high atomic mass of tungsten in the compound WS2 makes it a stand-out choice for high energy radiation detection applications. This is because, high energy photon-matter interactions including, the photoelectric effect (PE), Rayleigh scattering (RS) and Compton scattering (CS) depend strongly of the atomic mass, Z. Specifically the cross-section of such processes depends on the atomic mass as Z as.'24-5, Z2 and Z for the PE, RS and CS processes respectively. To this end we fabricate a simple vertical heterostructure consisting of Au-WS2-aC as depicted in the inset to Figure 6A. A large bias of 5 V is then applied across the WS2 whilst monitoring the current. We then expose them to a high energy gamma radiation source; in this case we used a 60Co source which emits photons at 1.17 and 1.33 MeV. As soon as the sample is exposed to the radiation, we observe a rapid increase of the current as a result of photo-excited carriers, see the middle inset of Figure 6A. The sample is then exposed to a high dose amounting to 30 KGy. Initially the conductivity of the sample increases which we attribute to doping due to an increase of sulphur vacancies in the WS2 which are known to n-type dope the W52. After -10Gry's this increase saturates and the conductivity drops proportional to the log of the dose, loc-log(dose). This decrease is attributed to irreversible crystallographic damage of the WS2 at high exposure levels. After the prolonged exposure the device was removed from the radiation source and the temporal response once again measured, Figure 6B displays 5 successive 5 Gy exposures. These results indicate that abraded WS2 films could be useful for future high energy radiation detector applications, especially suited for high dose environments such as nuclear reactors or space probe applications.
Triboelectric nanogenerator S The triboelectric effect in 2D materials has recently been reported. Those previous devices were mainly based on thin films based on liquid phase exfoliated. Here we demonstrate the use of mechanically abraded thin films for the use as a triboelectric effect. Figure 7A shows the schematic of the setup with a thin PET substrate with the abraded film or multilayer stack stuck to a large metallic plate which was kept grounded. A PDMS pad was then pressed onto the 2D material, which has the effect of charging the film. This sets a voltage relative to ground and this voltage drop is measured over a fixed resistor to calculate the current. We find that simple graphitic films can lead directly to a triboelectric effect with a power output of 0.36 mW when the pad is released from the 2D material. Furthermore, when a multilayer stack is produced such as Graphite/M0S2 then the effect is significantly increased with a max power output of 1.44 mW.
Given the simplicity that the films can be produced makes mechanically abraded films and heterostructures suitable for future triboelectric generator devices.
As described hereinbefore, complex functional heterostructure devices can be built up from 2D nanocrystals through a simple mechanical abrasion method. This technology allows for the rapid up-scaling of heterostructures and it is demonstrated that it has practical use in several simple device applications including conductive few layer graphene coatings, photodetectors. We have extended the technology and demonstrated the successful creation of various more complex vertical heterostructure devices including, multi-layer photovoltaics. We also show that abraded WS2 coatings can be used directly as electro catalysts for the HER reaction. The ease with which the films can be applied, and simplicity of up-scalability makes this technology significantly attractive for a large variety of applications.
Whilst specific embodiments of the invention are described hereinbefore, it will be appreciated that a wide range of modifications and alterations may be made thereto without departing from the scope of the invention as defined by the appended claims.
Claims (9)
- CLAIMS: 1. A method for use in the fabrication of a van der Waals heterostructure, the method comprising the steps of applying a mask to a substrate, rubbing a first material against the substrate to deposit and apply, by abrasion, a first layer of the first material to the substrate, applying a second mask over the first layer, and rubbing a second material against the substrate to apply, by abrasion, a second layer of the second material over at least part of the first layer.
- 2. A method according to Claim 1, wherein the second material is less hard or less abrasive than the first material.
- 3. A method according to Claim 1 or Claim 2, wherein the steps of rubbing the first and second materials against the substrate are achieved using a rotatable head.
- 4. A method according to Claim 3, wherein the material to be deposited is applied to the rotatable head or between the substrate and the head, and the material is deposited onto the substrate by pressing the head against the substrate whilst rotating the head, and moving the head relative to the substrate to apply the material over an area of the substrate, thereby applying a layer of the material to the substrate.
- 5. A method according to any of the preceding claims, and further comprising adding one or more further layers using this technique.
- 6. A method according to any of the preceding claims, and further comprising transferring a prefabricated element to the substrate.
- 7. A method according to Claim 6, wherein the prefabricated element comprises a layer fabricated using a CVD technique.
- 8. A multi-layered structure fabricated using the method of any of the preceding claims.
- 9. A structure according to Claim 8 and comprising at least one of a photo detector, a light emitting device, a transistor, a capacitor, a resistor, a superconducting memory device, a single photon emitter located on a film, a triboelectric generators and a hydrogen evolution catalyst.
Priority Applications (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB1917317.8A GB2589356A (en) | 2019-11-28 | 2019-11-28 | Van der Waals heterostructures |
PCT/EP2020/083611 WO2021105343A1 (en) | 2019-11-28 | 2020-11-27 | Van der waals heterostructures |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB1917317.8A GB2589356A (en) | 2019-11-28 | 2019-11-28 | Van der Waals heterostructures |
Publications (2)
Publication Number | Publication Date |
---|---|
GB201917317D0 GB201917317D0 (en) | 2020-01-15 |
GB2589356A true GB2589356A (en) | 2021-06-02 |
Family
ID=69147081
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
GB1917317.8A Withdrawn GB2589356A (en) | 2019-11-28 | 2019-11-28 | Van der Waals heterostructures |
Country Status (2)
Country | Link |
---|---|
GB (1) | GB2589356A (en) |
WO (1) | WO2021105343A1 (en) |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN114062279B (en) * | 2021-10-12 | 2023-02-03 | 暨南大学 | Single-particle spectrum electric tuning platform based on two-dimensional material and preparation and regulation method |
Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP1160880A2 (en) * | 2000-05-30 | 2001-12-05 | Kurt L. Barth | Apparatus and processes for the mass production of photovoltaic modules |
WO2009017859A2 (en) * | 2007-08-02 | 2009-02-05 | The Texas A & M University System | Dispersion, alignment and deposition of nanotubes |
US20130330231A1 (en) * | 2012-04-06 | 2013-12-12 | Massachusetts Institute Of Technology | Methods for deposition of materials including mechanical abrasion |
US20160195504A1 (en) * | 2014-08-20 | 2016-07-07 | Massachusetts Institute Of Technology | Methods and devices for deposition of materials on patterned substrates |
Family Cites Families (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US9190509B2 (en) * | 2013-03-11 | 2015-11-17 | The United States Of America As Represented By The Secretary Of The Army | High mobility, thin film transistors using semiconductor/insulator transition-metal dichalcogenide based interfaces |
ES2575711B2 (en) * | 2014-12-31 | 2016-11-03 | Universidade De Santiago De Compostela | Method for obtaining graphene sheets |
US11575006B2 (en) * | 2018-03-20 | 2023-02-07 | The Regents Of The University Of California | Van der Waals integration approach for material integration and device fabrication |
-
2019
- 2019-11-28 GB GB1917317.8A patent/GB2589356A/en not_active Withdrawn
-
2020
- 2020-11-27 WO PCT/EP2020/083611 patent/WO2021105343A1/en active Application Filing
Patent Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP1160880A2 (en) * | 2000-05-30 | 2001-12-05 | Kurt L. Barth | Apparatus and processes for the mass production of photovoltaic modules |
WO2009017859A2 (en) * | 2007-08-02 | 2009-02-05 | The Texas A & M University System | Dispersion, alignment and deposition of nanotubes |
US20130330231A1 (en) * | 2012-04-06 | 2013-12-12 | Massachusetts Institute Of Technology | Methods for deposition of materials including mechanical abrasion |
US20160195504A1 (en) * | 2014-08-20 | 2016-07-07 | Massachusetts Institute Of Technology | Methods and devices for deposition of materials on patterned substrates |
Also Published As
Publication number | Publication date |
---|---|
GB201917317D0 (en) | 2020-01-15 |
WO2021105343A1 (en) | 2021-06-03 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
Saraf et al. | Self-powered photodetector based on electric-field-induced effects in MAPbI3 perovskite with improved stability | |
Du Pasquier et al. | Dye sensitized solar cells using well-aligned zinc oxide nanotip arrays | |
Pataniya et al. | MoS2/WSe2 nanohybrids for flexible paper-based photodetectors | |
Zhou et al. | Utilizing interlayer excitons in bilayer WS2 for increased photovoltaic response in ultrathin graphene vertical cross-bar photodetecting tunneling transistors | |
Hahn et al. | BiSI micro-rod thin films: efficient solar absorber electrodes? | |
Cai et al. | Strain-modulated photoelectric responses from a flexible α-In2Se3/3R MoS2 heterojunction | |
Pareek et al. | Fabrication of large area nanorod like structured CdS photoanode for solar H2 generation using spray pyrolysis technique | |
US20150364614A1 (en) | Detector | |
Shooshtari et al. | Ultrafast and stable planar photodetector based on SnS2 nanosheets/perovskite structure | |
Nawaz et al. | Flexible photodetectors with high responsivity and broad spectral response employing ternary Sn x Cd1–x S micronanostructures | |
WO2018195383A1 (en) | Two-dimensional material with electroactivity and photosensitivity | |
Wei et al. | High-performance self-driven photodetectors based on self-polarized Bi0. 9Eu0. 1FeO3/Nb-doped SrTiO3 pn heterojunctions | |
Akbari et al. | Highly sensitive, fast-responding, and stable photodetector based on ALD-developed monolayer TiO 2 | |
WO2021105343A1 (en) | Van der waals heterostructures | |
Zhang et al. | Two-dimensional perovskite Sr2Nb3O10 nanosheets meet CuZnS film: facile fabrications and applications for high-performance self-powered UV photodetectors | |
Yang et al. | Wafer-scale growth of Sb2Te3 films via low-temperature atomic layer deposition for self-powered photodetectors | |
Nguyen et al. | Piezoelectricity-enhanced multifunctional applications of hydrothermally-grown p-BiFeO3–n-ZnO heterojunction films | |
Fu et al. | Layer and material-type dependent photoresponse in WSe2/WS2 vertical heterostructures | |
Mao et al. | Wafer-scale 1T′ MoTe2 for fast response self-powered wide-range photodetectors | |
Song et al. | High-performance photodetector based on the ReSe2/PtSe2 van der Waals heterojunction | |
Bapathi et al. | Passivation-free high performance self-powered photodetector based on Si nanostructure-PEDOT: PSS hybrid heterojunction | |
Mukherjee et al. | Probing bias and power dependency of high-performance broadband Mg/ZnSnP2/Sn back-to-back Schottky junction photodetectors | |
US10903378B2 (en) | Photovoltaic cells comprising a layer of crystalline non-centrosymmetric light-absorbing material and a plurality of electrodes to collect ballistic carriers | |
Guo et al. | Tunnel barrier photoelectrodes for solar water splitting | |
Qiu et al. | Ferroelectricity-Driven Self-Powered Weak Temperature and Broadband Light Detection in MoS2/CuInP2S6/WSe2 van der Waals Heterojunction Nanoarchitectonics |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |