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- 摘要
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Controlled Synthesis of Large Scale Continuous monolayer WS2 Film by Atmospheric Pressure Chemical Vapor Deposition
摘要： Synthesis of monolayer transition metal dichalcogenides (TMDs) in large-size is crucial to their practical applications in electronics and optoelectronics. Here, large scale continuous monolayer WS2 film has been successfully grown by atmospheric pressure chemical vapor deposition (APCVD) method. By modulating three growth parameters, Ar gas flow rate, the temperature of WO3 precursor and the distance between substrate and WO3 precursor, WS2 film with different grain size can be obtained. At optimal processing condition, large-scale monolayer WS2 with lateral dimension can reach 1 millimeter above. This would pave the way for scale production of continuous monolayer TMDs film.
关键词： large scale,monolayer WS2,atmospheric pressure chemical vapor deposition,continuous film
更新于2025-09-16 10:30:52
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Electrical and optical properties of the specimens with graphene quantum dots prepared by different number of wet transfer
摘要： Graphene quantum dots (GQDs) are grown on the copper foil substrate by the chemical vapor deposition (CVD) synthesis. 1–3 wet transfer numbers are then used in the preparations of the GQDs/glass substrate in order to improve the density and uniformity of GQDs via the stacking of multiple layers. The CH4 input time, ?ow rate, and the number of wet transfer are determined to obtain the optimum conditions in electrical (resistivity) and optical (transmittance) properties. The multilayered graphene is characteristically close to the graphite-like material. The G-band peak intensity in Raman analyses is varied proportional to the density of GQDs. Increasing the wet transfer number can lead to increases in the mean diameter of GQDs and the amount of oxygen vacancies, thus resulting in the rise of carrier concentration and the lowering of carrier mobility. The resistivity varying with the wet transfer number is inversely proportional to the density of GQDs. A bandgap reduction can bring in the lowerings of photoluminescence peak intensities. The specimen with 2 wet transfers has the lowest resistivity and the second highest transmittance of these specimens. GQDs can bring in a signi?cant reduction of resistivity compared to the same substrate without GQD.
关键词： Graphene quantum dots,Wet transfer method,Chemical vapor deposition,Graphite-like material
更新于2025-09-16 10:30:52
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Development of a fully automated desktop chemical vapor deposition system for programmable and controlled carbon nanotube growth
摘要： We have rationally designed and developed a fully automated desktop furnace system that enables programmable chemical vapour deposition growth of carbon nanotubes with controlled height, density, and pattern architecture. Comprising several essential components involving a heating furnace, mass flowmeters, and computer controller, the developed system realizes controlled and practical carbon nanotube growth without resort to expensive and ponderous instruments. By programming, modifying, and loading the reusable recipes in the developed system, systematic and reproducible growths of carbon nanotubes with desired morphology and dimension can be performed. Growth results with controlled height, density, and pattern are demonstrated through the actual operations, confirming the validity and usefulness of the developed system towards various practical applications.
关键词： Furnace,Programmable growth recipe,Desktop system,Chemical vapor deposition,Micropattern,Automated control,Nanopattern,Carbon nanotube
更新于2025-09-16 10:30:52
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[IEEE 2019 6th International Conference on Space Science and Communication (IconSpace) - Johor Bahru, Malaysia (2019.7.28-2019.7.30)] 2019 6th International Conference on Space Science and Communication (IconSpace) - Integration of NiO Layer as Hole Transport Material in Perovskite Solar Cells
摘要： A successful integration of inorganic hole transporting material (HTM) for perovskite become one of the major concerns due to the instability issue with organic HTM. Inorganic NiO films as an efficient HTM for the inverted perovskite solar cell has been deposited by electron beam vapor deposition (EBPVD) technique instated of solution process. The X-Ray diffraction (XRD) peak of as-deposited substrate corresponding to (1 1 1) and (2 0 0) plane are dominating. The non-stoichiometry (1 1 1) in NiO thin film formation at influence its charge transfer characteristics. The FESEM confirms the successful non-stoichiometric deposition of NiO on FTO glass in an elemental wt% of O2 (15.82) and Ni (23.62). The perovskite structure of solar cells are fabricated Glass/TCO/NiO/Perovskite/PCBM/BCP/Ag. The deposited perovskite solar cells show higher power conversion efficiency (PCE) 10.80% with short circuit current density (Jsc) of 15.13 (mA cm-2), open circuit voltage (Voc) of 0.967 (V), field factor (FF) of 73.83 (%) which also allows thinking of an alternative HTL other than organic HTL for realistic commercial purpose.
关键词： Perovskite solar cell,hole transporting materials,nickel oxide,vapor deposition technique,power conversion efficiency
更新于2025-09-16 10:30:52
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Chirality control for predominant metallic or semiconducting single-walled carbon nanotubes prepared using a mild etchant
摘要： Highly oriented metallic and semiconducting SWCNTs were synthesized with different carrier gas compositions and etchants by the floating catalyst chemical vapor deposition method. The addition of acetone as an etchant resulted in metallic nanotubes. The acetone acted as both an additional carbon source and etching agent for carbon nanotube nucleation.
关键词： Chirality control,Metallic,Floating catalyst chemical vapor deposition,Single-walled carbon nanotubes,Acetone,Semiconducting,Etchant
更新于2025-09-16 10:30:52
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Monolayer MoSe <sub/>2</sub> /NiO van der Waals heterostructures for infrared light-emitting diodes
摘要： Nowadays monolayer transition metal chalcogenides (TMCs) have been widely researched due to their excellent optoelectronic properties. However, the preparation of large-sized monolayer TMCs and high-power TMC-based light-emitting diodes are still full of challenges, which limit their application in two-dimensional devices. Here, the large-sized monolayer single-crystalline MoSe2 was synthesized by chemical vapor deposition. The influence of the relative gas pressure ratio of MoO3 to Se on MoSe2 morphology is discussed. The TEM analysis confirmed the presence of 2H-phase monolayer MoSe2. A photoluminescence peak from the MoSe2 monolayer is detected at about 804 nm, illustrating an intrinsic energy bandgap of 1.54 eV. Importantly, a novel 2D/3D heterostructure, monolayer MoSe2/NiO van der Waals heterostructure, is constructed for a light-emitting diode (LED). The electroluminescence peaks of n-MoSe2/p-NiO LED locate at 812 nm, 848 nm and 918 nm, all of which are in the infrared light range. Interestingly, the electroluminescence peaks of our n-MoSe2/p-NiO LED are close to those of conventional air conditioner telecontrollers. So the n-MoSe2/p-NiO infrared LED is forward to be used in infrared remote sensing systems in the future.
关键词： van der Waals heterostructures,infrared light-emitting diodes,Monolayer MoSe2,chemical vapor deposition,NiO
更新于2025-09-16 10:30:52
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Synthesis, characterization and UV photodetector application of Sb-doped ZnO nanowires
摘要： Sb-doped ZnO nanowires with hexagonal wurtzite structures have been synthesized via chemical vapor deposition method, and the main charge state of Sb dopants is Sb5+. The photoluminescence spectra demonstrate the existence of shallow acceptors, SbZn-2VZn complexes in all probability. On the other hand, Sb doping caused more native and impurity donors in Sb-doped ZnO nanowires. Then, field effect transistors of single Sb-doped ZnO nanowire were fabricated and the transport properties shows n-type conductivity. The competition between shallow acceptors and donors, and the influence of Sb valency need to be investigated further to obtain stable Sb-doped p-type ZnO. At last, we have shown the potential application of Sb-doped ZnO nanowires for nanoscale UV photodetector.
关键词： field effect transistors,UV photodetector,Sb-doped ZnO nanowires,photoluminescence,chemical vapor deposition
更新于2025-09-16 10:30:52
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Synthesis of Monolayer MoSe2 with Controlled Nucleation via Reverse-Flow Chemical Vapor Deposition
摘要： Two-dimensional (2D) layered semiconductor materials, such as transition metal dichalcogenides (TMDCs), have attracted considerable interests because of their intriguing optical and electronic properties. Controlled growth of TMDC crystals with large grain size and atomically smooth surface is indeed desirable but remains challenging due to excessive nucleation. Here, we have synthesized high-quality monolayer, bilayer MoSe2 triangular crystals, and continuous thin films with controlled nucleation density via reverse-flow chemical vapor deposition (CVD). High crystallinity and good saturated absorption performance of MoSe2 have been systematically investigated and carefully demonstrated. Optimized nucleation and uniform morphology could be achieved via fine-tuning reverse-flow switching time, growth time and temperature, with corresponding growth kinetics proposed. Our work opens up a new approach for controllable synthesis of monolayer TMDC crystals with high yield and reliability, which promote surface/interface engineering of 2D semiconductors towards van der Waals heterostructure device applications.
关键词： controlled growth,transition metal dichalcogenides (TMDCs),MoSe2,reverse-flow chemical vapor deposition (CVD)
更新于2025-09-16 10:30:52
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Inserting dome shape microstructure for enhancement of ultraviolet photodetector performance of n-ZnO nanorods/p-Si heterojunction
摘要： A mixed intermediate layer of silica and zinc oxide (SZO) with architecturally dome-shaped microstructure is fabricated and characterized by combining a hydrothermal method and a plasma-enhanced chemical vapor deposition technique. Our results demonstrated that 200 (cid:1)C was an optimum deposition temperature for dome shape architecture SZO layer, acting as an antire?ection layer in the ultraviolet range and buffer layer for growth ZnO nanorods (NRs) arrays. Consequently, at 2.0 V reverse bias, the photo-to-dark current ratio measured with an p-Si/n-ZnONRs photodiode employing the dome-shaped SZO layer is improved by almost three orders of magnitude in the ultraviolet range as compared to that under visible-light illumination.
关键词： ZnO nanorods,Hydrothermal growth,Plasma-enhanced chemical vapor deposition,Photodiodes
更新于2025-09-16 10:30:52
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High-efficiency Posture Pre-alignment Method for Large Component Assembly via iGPS and Laser Ranging
摘要： A model for controlling the two-dimensional distribution of negatively charged nitrogen-vacancy (NV?) fluorescent centers near the surface of a diamond crystal is presented, using only a microwave plasma-assisted chemical vapor deposition (CVD) method. In this approach, a CVD diamond layer is homoepitaxialy grown via microwave plasma-assisted CVD using an isotopically enriched methane (12CH4 ), hydrogen (H2 ), and nitrogen (N2 ) gas mixture on patterned diamond (0 0 1). When the surface is imaged by means of confocal microscope photoluminescence mapping, fine grooves are observed to have been generated artificially on the diamond surface. NV? centers are found to be distributed selectively into these grooves. These results demonstrate an effective means for the formation of NV? centers of selectable size and density via microwave plasma-assisted CVD, with potential application in the production of diamond quantum sensors.
关键词： doping,nitrogen-vacancy centers,homoepitaxial,groove structure,Diamond,microwave plasma-assisted chemical vapor deposition
更新于2025-09-16 10:30:52