- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
AIP Conference Proceedings [AIP Publishing 15th International Conference on Concentrator Photovoltaic Systems (CPV-15) - Fes, Morocco (25–27 March 2019)] 15th International Conference on Concentrator Photovoltaic Systems (CPV-15) - Zone melting recrystallization of microcrystalline silicon ribbons obtained by chemical vapor deposition
摘要： We present the results achieved with an optical zone melting recrystallization (ZMR) system, which concentrates the radiation of two halogen lamps on the surface of a microcrystalline silicon (μc-Si) ribbon sample, creating a long, 2 mm width molten region (~1414o C). μc-Si ribbon samples measuring up to 25×100 mm2 were previously obtained using an inline optical chemical vapor deposition (CVD) system, that grows silicon layers on top of a silicon dust substrate. Inside the ZMR system, the μc-Si ribbon sample is recrystallized in an argon atmosphere and using a step motor to pull the ribbon at a constant speed between 1 to 6 mm/min, the molten zone travels along the ribbon, recrystallizing the whole sample into a multi-crystalline silicon (mc-Si) ribbon, with an average crystal size in the [1; 10] mm range. It was observed that the physical characteristics of the μc-Si ribbon, like powder substrate incorporation, porosity, thickness, powder grain size used as substrate in the CVD step, have a crucial influence on the recrystallization process and on the electrical properties of the mc-Si ribbon obtained after the ZMR process. Lifetime measurements performed on the recrystallized samples suggest that improvements regarding crystalline quality and possible presence of impurities need to be addressed.
关键词： microcrystalline silicon,solar cells,Zone melting recrystallization,multi-crystalline silicon,chemical vapor deposition
更新于2025-09-12 10:27:22
-
Growth of CdSe/MoS2 vertical heterostructures for fast visible-wavelength photodetectors
摘要： Heterostructures composed of different semiconducting materials have aroused wide attentions due to their fascinating properties originated from the interfaces. Particularly, the recent two dimensional layered materials (2DLM) have provided novel platforms to flexibly design the heterostructures for diverse electronic and optoelectronic applications. In this work, we have reported the growth of CdSe nanoplates/MoS2 monolayer vertical heterostructures with efficient and fast visible-wavelength photodetections. Highly dense CdSe nanoplates were vertically assembled on monolayer MoS2 through a two-step chemical vapor deposition (CVD) process. The interfacial photoinduced charge behaviors were investigated in detail via the time resolution photoluminescence (TRPL) measurements, revealing the efficient charge transfer across the heterointerface. Benefiting from the large CdSe coverage and efficient charge transfer, superior photodetection performances of the CdSe/MoS2 heterostructures can be obtained with an enhanced photoresponsivity of 1.63 A/W, which can be further improved to be 12 A/W via applying the gate voltage. Besides, the heterostructure detectors also exhibit a very fast photoresponse speed of 370 μs, much faster than previous photodetectors based on CVD-grown 2D heterostructures. The as-synthesized CdSe/MoS2 heterostructures may find important applications in integrated optoelectronic systems.
关键词： Responsivity,Chemical vapor deposition,Photodetectors,Vertical heterostructures,CdSe/MoS2
更新于2025-09-12 10:27:22
-
Graphene Quantum Dots Promoted the Synthesis of Heavily n-Type Graphene for Near-Infrared Photodetectors
摘要： The application of graphene in the field of microelectronics is becoming more and more urgent with the emergence of bottlenecks in semi-technical development, in which controllable graphene doping technology, therefore, strongly demanded to tune the electronic or optoelectronic properties for the fabrication of high-performance devices. We herein report a simple and convenient approach to synthesize heavily nitrogen (N) and phosphorus (P) co-doped graphene (n-type graphene) by chemical vapor deposition (CVD), which is realized by utilizing N and P co-doped graphene quantum dots (n-type GQDs) as a nucleation centers, methane (CH4) as the gaseous carbon reservoir, and copper (Cu) foils as the catalyst substrate. By the monitoring of the growth mechanism of the graphene, and an investigation revealed that co-doped GQDs could serve as the nucleation sites for producing doped-graphene films through two-dimensional epitaxial growth. Finally, the photodetector built on the heavily n-type graphene film is confirmed to perform satisfactorily, accompanying high detectivity (~1.3×1010 cmHz1/2W-1) and responsivity (58 mAW-1), at a wavelength of 1550 nm. A simple and environmentally friendly graphene doping technology has been developed, which promotes the application of doped graphene in the field of microelectronics.
关键词： quantum dots,photodetectors,chemical vapor deposition,n-type doping,graphene
更新于2025-09-12 10:27:22
-
Controlled joule-heating of suspended glassy carbon wires for localized chemical vapor deposition
摘要： This paper demonstrates for the first time localized chemical vapor deposition of WO3-x on a suspended glassy carbon wire. A process based on the photopatterning of an SU-8 scaffold, the near-field electrospinning of an SU-8 fiber, and their pyrolysis yields a monolithic carbon structure featuring a glassy carbon wire of known diameter and length, suspended on a glassy carbon scaffold. The temperature required for the deposition of WO3-x is generated by passing current through the wire, which causes Joule heating. The deposition starts in the midpoint of the wire, and extends to its ends as the current is increased. The thickness and length of the coating are functions of the imposed current. The evolution of the coating can be monitored in real time by measuring the voltage vs current characteristic of the wire. We have deposited WO3-x coatings with thickness from 71 nm to 1.4 μm, in glassy carbon wires with diameters between 780 nm and 2.95 μm. The coatings are uniform and polycrystalline. The suspended glassy carbon wire is a generic platform for the deposition of many transition metal oxide (TMO) coatings, and opens the door to carbon-TMO structures for applications including catalysis and gas sensing.
关键词： glassy carbon wire,gas sensing,localized chemical vapor deposition,WO3-x,catalysis,Joule heating,transition metal oxide
更新于2025-09-12 10:27:22
-
Field emission property of vertically aligned nitrogen-doped multi-walled carbon nanotubes produced by chemical vapor deposition
摘要： Vertically aligned nitrogen-doped multi-walled carbon nanotubes (N-MWNTs) were synthesized by the chemical vapor deposition (CVD) at 900 °C using imidazole mixed with ferrocene as carbon and nitrogen sources, and catalyst, respectively. The effects of ammonia (NH3) and hydrogen (H2) flow rates on the growth of N-MWNTs were investigated (hereafter referred to A-N-MWNTs and H-N-MWNTs, respectively). Transmission electron microscopy (TEM) revealed the bamboo-like structure of the N-MWNTs, in which the separation between individual bamboo compartments decreased with increasing nitrogen concentration in N-MWNTs. X-ray photoelectron spectroscopy (XPS) analysis results supported that the nitrogen concentrations in N-MWNTs is 0.55 at.%, whereas A-N-MWNTs and H-N-MWNTs with the flow rate at 10 standard cubic centimeters per minute (sccm) (10A-N-MWNTs and 10H-N-MWNTs, respectively) showed 1.14 and 4.06 at.%, respectively. We found that the optimal conditions for the highest nitrogen-doped multi-walled carbon nanotubes (MWNTs) was a flow rate of NH3 and H2 at 10 sccm. Results from field emission measurements indicated that the turn-on fields of N-MWNTs, 10A-N-MWNTs and 10H-N-MWNTs were 6.7, 4.3 and 3.1 V/μm, respectively, while the field enhancement factors (β) were 5230, 10,805 and 20,390, respectively. Furthermore, the current density of N-MNWTs increased with increasing the nitrogen atoms in MWNTs. The results support that field emission based on N-MWNTs is a good emitter with low turn-on field and large field enhancement factor. Nitrogen doping in MWNTs makes them attractive candidates as high-performance field emitters.
关键词： Field emission,Nitrogen-doped multi-walled carbon nanotubes,Chemical vapor deposition
更新于2025-09-12 10:27:22
-
Controllable Synthesis of Crystalline ReS <sub/>2(1?</sub><i> <sub/>x</sub></i> <sub/>)</sub> Se <sub/>2</sub><i> <sub/>x</sub></i> Monolayers on Amorphous SiO <sub/>2</sub> /Si Substrates with Fast Photoresponse
摘要： Re-based transition metal dichalcogenides (TMDs) and alloys have many unusual features such as in-plane anisotropic optical, electrical, and phonon properties and thus receive increasing research interest. However, the distorted 1T structure and the weaker interlayer coupling easily cause anisotropic growth and out-of-plane growth, making it particularly challenging to produce Re-based TMD and alloy monolayers on amorphous SiO2/Si substrates. Here, a reliable method is developed for the synthesis of high-quality and large-size ReS2(1?x)Se2x monolayer crystals on SiO2/Si substrates by NaCl-assisted, confined-space chemical vapor deposition. The synergy of salt assistance with the confined reaction space facilitates the formation of intermediate metal oxychlorides and creates a relatively stable growth environment, finally leading to the successful synthesis of ReS2(1?x)Se2x monolayer crystals on SiO2/Si substrates. The as-grown ReS2(1?x)Se2x monolayer alloys exhibit continuously variable composition, high crystal quality, and uniform distribution of Re, S, and Se elements. Furthermore, the ReS2(1?x)Se2x based photodetectors display good photoresponse to visible and near-infrared light with a fast response of less than 15 ms. The salt-assisted, confined-space chemical vapor deposition provides a reliable way for the synthesis of large-scale low-lattice symmetry 2D materials on amorphous SiO2/Si substrates and opens up new prospects for Re-based TMDs and alloys in optoelectronic devices.
关键词： ReS2(1?x)Se2x monolayers,NaCl,chemical vapor deposition,confined-space,photoresponse
更新于2025-09-12 10:27:22
-
-Ga2O3 substrate enabled by self-assembled SiO2 nanospheres
摘要： To obtain high-quality GaN epitaxial ?lm on (?2 0 1) β-Ga2O3 substrate, periodic SiO2 nanosphere monolayer was self-assembled followed by inductively coupled plasma (ICP) etching. This periodic SiO2 nanosphere patterned Ga2O3 substrate (SiO2-NPGS) enables nanoscale epitaxial lateral overgrowth (NELOG) of GaN ?lm. Compared to planar Ga2O3 substrate, SiO2-NPGS shows great potential for epitaxial GaN with (0 0 0 2) and (1 0 ?1 2) full-width at half-maximum (FWHM) reduced from 555 to 388 arcsec, and 634 to 356 arcsec, respectively. Raman spectra also con?rm that the as-grown GaN ?lm on SiO2-NPGS is almost stress-free. The dislocation reduction is also observed by cross-sectional transmission electron microscope (TEM). The embedded SiO2-nanosphere blocks the dislocations and induces the GaN lateral overgrowth, thus leading to the signi?cant reduction of the threading dislocation densities. These ?ndings provide a new way for high quality stress-free GaN ?lm epitaxial growth on Ga2O3 substrate.
关键词： A3 Metal organic chemical vapor deposition,B1 SiO2 nanosphere,B1 Ga2O3,B1 GaN,A1 Nanoscale epitaxial lateral overgrowth
更新于2025-09-12 10:27:22
-
Back-to-back Schottky junction photodetectors based on CVD grown CsPbBr <sub/>3</sub> microcrystalline striped films
摘要： In recent years, a new type of lead halide perovskite has attracted a lot of attention for next-generation photodetectors (PDs) with high responsivity, good detectivity, and fast photoresponse speed. Specifically, cesium based all-organic perovskites exhibit better photostability and therefore have achieved increasing success in PDs recently. For reducing the leak current and increasing the response speed of photo-conductive PDs, back-to-back Schottky junction PD is designed and fabricated through a direct growth approach of CsPbBr3 microcrystal (MC) films on indium tin oxide (ITO) electrodes by the chemical vapor deposition (CVD) method. Due to the enhanced Schottky barrier height and threshold voltage between CsPbBr3 and ITO electrodes, the PD exhibits the on/off ratio of up to 104, peak responsivity of 3.9 AW?1, detectivity of 3.8 × 1012, and fast response speed of 0.22 ms (rise time) and 0.45 ms (decay time). In addition, the stability of PD is also enhanced by the high crystal quality of CVD grown CsPbBr3 MCs.
关键词： microcrystalline films,Schottky junction,photodetectors,CsPbBr3,chemical vapor deposition
更新于2025-09-12 10:27:22
-
Oxidising and carburising catalyst conditioning for the controlled growth and transfer of large crystal monolayer hexagonal boron nitride
摘要： Hexagonal boron nitride (h-BN) is well-established as a requisite support, encapsulant and barrier for 2D material technologies, but also recently as an active material for applications ranging from hyperbolic metasurfaces to room temperature single-photon sources. Cost-effective, scalable and high quality growth techniques for h-BN layers are critically required. We utilise widely-available iron foils for the catalytic chemical vapour deposition (CVD) of h-BN and report on the significant role of bulk dissolved species in h-BN CVD, and specifically, the balance between dissolved oxygen and carbon. A simple pre-growth conditioning step of the iron foils enables us to tailor an error-tolerant scalable CVD process to give exceptionally large h-BN monolayer domains. We also develop a facile method for the improved transfer of as-grown h-BN away from the iron surface by means of the controlled humidity oxidation and subsequent rapid etching of a thin interfacial iron oxide; thus, avoiding the impurities from the bulk of the foil. We demonstrate wafer-scale (2”) production and utilise this h-BN as a protective layer for graphene towards integrated (opto-)electronic device fabrication.
关键词： monolayer,hexagonal boron nitride,transfer,2D materials,large crystal,chemical vapor deposition,encapsulation
更新于2025-09-12 10:27:22
-
Renewable and Sustainable Composites || Methodologies for Achieving 1D ZnO Nanostructures Potential for Solar Cells
摘要： One-dimensional (1D) nanostructures are generally used to describe large aspect ratio rods, wires, belts, and tubes. The 1D ZnO nanostructures have become the focus of research owing to its unique physical and technological significance in fabricating nanoscale devices. When the radial dimension of the 1D ZnO nanostructures decreases to some lengths (e.g., the light wavelength, the mean of the free path of the phonon, Bohr radius, etc.), the effect of the quantum mechanics is definitely crucial. With the large surface-to-volume ratio and the confinement of two dimensions, 1D ZnO nanostructures possess the captivating electronic, magnetic, and optical properties. Furthermore, 1D ZnO nanostructure’s large aspect ratio, an ideal candidate for the energy transport material, can conduct the quantum particles (photons, phonons, electrons) to improve the relevant technique applications. To date, many methods have been developed to synthesize 1D ZnO nanostructures. Therefore, methodologies for achieving 1D ZnO nanostructures are expressed, and the relevant potential application for solar cells are also present to highlight the attractive property of 1D ZnO nanostructures.
关键词： hydrothermal,nanostructures,one dimensional,ZnO,solar cell,chemical vapor transport and condensation (CVTC),vapor-liquid-solid (VLS),electrochemical,metal-organic chemical vapor deposition (MOCVD),chemical vapor deposition (CVD)
更新于2025-09-11 14:15:04