修车大队一品楼qm论坛51一品茶楼论坛,栖凤楼品茶全国楼凤app软件 ,栖凤阁全国论坛入口,广州百花丛bhc论坛杭州百花坊妃子阁

oe1(光电查) - 科学论文

189 条数据
?? 中文（中国） ▾

  • Surface-enhanced Raman scattering from buffer layer under graphene on SiC in a wide energy range from visible to near-infrared

    摘要： Raman signals from the buffer layer between graphene and a SiC substrate are enhanced through the formation of nano-structured Au deposited directly on graphene grown on SiC. This simple method makes it possible to deconvolute multiple graphene and buffer layer peaks in a wide energy range from 1.58 to 2.33 eV and find new buffer layer peaks that are not resolved in conventional Raman scattering spectroscopy. Furthermore, we clearly show a small linear excitation energy dependence for one of the buffer layer peak positions and an absence of energy dependence for the peaks at most of the other positions.

    关键词： buffer layer,Surface-enhanced Raman scattering,graphene,SiC,near-infrared

    更新于2025-09-23 15:19:57

  • Growth mechanism of porous 3Ca??SiC films prepared via laser chemical vapor deposition

    摘要： Porous SiC film is an excellent electrode material for robust micro-supercapacitors used in extremely harsh environments. In one of our previous studies, porous 3C–SiC film with high areal capacitance and high deposition rate was prepared via laser chemical vapor deposition (LCVD). However, it is still urgent to explore the formation mechanism of porous structures using LCVD. In this study, the microstructure of the porous cubic SiC film prepared via LCVD was analyzed in detail using scanning and transmission electron microscopy techniques. The growth mechanism of the deposits has been proposed according to the “growth competing theory” and “shadow effect theory.”

    关键词： Growth mechanism,Porous 3C–SiC film,Microstructure,Laser chemical vapor deposition (LCVD)

    更新于2025-09-23 15:19:57

  • Surface defects state analysis of laser induced graphene from 4H-SiC

    摘要： We demonstrate the surface defect type, density and related electrical modification of graphene sheet generated by 193-nm ArF excimer laser irradiation on n-type 4H-SiC. The charge density difference and partial density of states (PDOS) carried out by density functional theory (DFT) calculations predict the graphene with lattice imperfection can induce virtual bound states at the vacancy sites and Fermi level shift compared to perfect graphene. The surface defects density of laser generated graphene is characterized by nanoscale electrical measurements using the conductive atomic force microscope (c-AFM). The corresponding current–voltage (I–V) curves show that the electronic charge transfers, thereby electrical conductivities of laser generated graphene, are influenced by the lattice defects. The defect densities are tunable by change laser fluence and pulse number. This research provides an understanding of the interfacial transport properties between laser generated graphene and 4H-SiC through a detailed analysis of surface defects.

    关键词： SiC,Interfacial transport,Laser,Graphene,Surface defect

    更新于2025-09-23 15:19:57

  • An optimized Graphene/4H-SiC/Graphene MSM UV-photodetector operating in a wide range of temperature

    摘要： In this paper, .an accurate analytical model has been developed to optimize the performance of an Interdigitated Graphene Electrode/p-silicon carbide (IGE/p-4H-SiC) Metal semiconductor fitness function for the multi objective optimization (MOGA) approach. The optimized sensitivity and speed performances was executed. Our results confirm the excellent ability of the suggested Graphene electrode system to decrease the unwanted shadowing effect. A responsivity of 238 μA/W was obtained under 325-nm illumination compared to the 16.7 μA/W for the conventional Cr-Pd/p-SiC PD. A photocurrent to- dark-current ratio (PDCR) of 5.75 × 105 at 300K and 270 at 500K was distinguished. The response time was found to be around 14 μs at 300K and 54.5 μs at 500K. Furthermore, the developed model serves as a fitness function to recognize the IGE formalism pattern which permits the enhancement of the performance of the proposed Gr/4H-SiC IE MSM PD using MOGA-based technique. The achieved results indicate that the suggested design methodology not only permits to realize a superior compromise amid responsivity and response time, but also shed light on the proposed device’s ruggedness under high temperature conditions. This opens the way to realize ultra-sensitive, high-speed SiC optoelectronic devices for extremely high temperature applications.

    关键词： Analytical Model,UV photodetector,Graphene,MOGA approach,4H-SiC,interdigitated electrodes

    更新于2025-09-23 15:19:57

  • Performance analysis of cubic silicon carbide solar cell as an appropriate candidate for high temperature application

    摘要： In this research article, a 3C–SiC-based single-junction solar cell is evaluated using a two-dimensional finite element method. Effects of n + and p + thicknesses and operating temperature on the performance of n + pp + 3C–SiC solar cell are simulated to find its real efficiency. For a cell with a thickness of 5 μm, the efficiencies of 12.52%, 11.2%, 10.3%, and 8.8% are obtained for n + and p + thicknesses of 0.2 μm, 0.3 μm, 0.4 μm, and 0.5 μm, respectively. It is investigated that the conversion efficiency of a Si-based solar cell is very sensitive to temperature variation. It significantly decreases when the temperature increases while 3C–SiC benefits from the best thermal stability. The efficiency gradients of 0.015%/oK and 0.0087%/oK are obtained from numerical and limitation methods for the 3C–SiC-based solar cells, respectively. It is important to mention that this value is 0.0375%/oK for a single-junction silicon solar cell.

    关键词： Silicon solar cells,Silicon carbide,High bandgap,High temperature,3C–SiC

    更新于2025-09-23 15:19:57

  • Femtosecond laser modification of 6Ha??SiC crystals for waveguide devices

    摘要： We report on optical waveguides produced by a femtosecond laser in 6H–SiC crystals. Their guiding properties have been investigated at a wavelength of 1064 nm, and confocal micro-Raman images have been obtained at an excitation wavelength of 532 nm. The results demonstrate that mode pro?les can be tailored by the adjustment of writing parameters, and the blueshift of the spectrum (at around 787.05 cm?1) mainly takes place in the irradiated areas. From images of Raman intensity and spectral shift, it is obvious that optical properties in guiding regions are well preserved. These waveguides may have potential applications in integrated optics and quantum photonics.

    关键词： femtosecond laser,6H–SiC crystals,optical waveguides,quantum photonics,integrated optics

    更新于2025-09-23 15:19:57

  • Epitaxial growth and electrical performance of graphene/3Ca??SiC films by laser CVD

    摘要： High electrical conductivity graphene/epitaxial-3CeSiC (G/epi-3CeSiC) composite films have the potential to the applications such as micro-electro-mechanical systems, distributed Bragg reflectors, solar cells, and photocatalysis in harsh environments. In this study, G/epi-3CeSiC composite films were prepared through laser chemical vapor deposition (LCVD) using hexametyldisilane (HMDS) as a safe single precursor. The electrical conductivity (s) of the composite films reached 2.23 (cid:1) 104 S/m, which is 2.2 times of the highest s reported for G/epi-3CeSiC composite. The deposition rate (Rdep) of the composite film with the highest s is 8.2 times of that of the G/epi-3CeSiC with the highest s ever reported. s of the pure epitaxial 3CeSiC film is only 81.2 S/m, which is the lowest value reported to date of 3CeSiC prepared through CVD using HMDS as a single precursor. Elimination of carbon is beneficial for increasing the breakdown field intensity and decreasing the leakage current of heterojunction when epitaxial 3CeSiC is used as semiconductor material.

    关键词： Electrical conductivity,Deposition rate,Laser CVD,Graphene/SiC film,Epitaxial

    更新于2025-09-23 15:19:57

  • A Schottky-junction-based platinum nanoclusters@silicon carbide nanosheet as long-term stable hydrogen sensors

    摘要： Hydrogen gas sensors which could be applied in harsh environments (high temperature, corrosion atmosphere, etc.) are highly demanded in special fields such as aerospace and chemical industry. Here, we have successfully produced a platinum nanoclusters@silicon carbide nanosheets (Pt NCs@SiC NSs) gas sensor via a simple one-step wet chemical reduction reaction. The Pt NCs@SiC NSs show good response (15.7%) towards 500 ppm hydrogen under 300 °C. Besides, this device possesses a good linear response towards different hydrogen concentration under 500 ppm and keeps a good stability in one month. The gas sensing properties of Pt NCs@SiC NSs are mainly from the Schottky junction-based structure, in which both reception and transduction process play important roles. This work provides a simple way to prepare high-temperature hydrogen sensors without complex equipment, and the large-scale preparation is also available.

    关键词： hydrogen sensing,Pt nanoclusters@SiC nanosheets,chemical reduction reaction,high-temperature

    更新于2025-09-23 15:19:57

  • Comparative study of radiation defect dynamics in 3C-SiC by X-ray diffraction, Raman scattering, and ion channeling

    摘要： At moderately elevated temperatures, radiation defects in SiC exhibit pronounced dynamic annealing, which remains poorly understood. Here, we study 3C-SiC bombarded at 100°C with pulsed beams of 500 keV Ar ions. Radiation damage is monitored by a combination of X-ray diffraction, Raman scattering, and ion channeling. Similar damage buildup behavior but with different defect relaxation time constants, ranging from ～1 to ～6 ms, is observed for the different types of lattice defects probed by these techniques. A correlation between relaxation times and the nature of the defects is proposed. These results reveal additional complexity of radiation defect dynamics in SiC and demonstrate that results of different defect characterization techniques are needed for a better understanding of dynamic annealing processes in solids.

    关键词： X-ray diffraction,Ion channeling,Raman scattering,Dynamic annealing,Radiation defects,3C-SiC

    更新于2025-09-23 15:19:57

  • Preparation of SiC Powders by Carbonthemal Reduction Method at Low Temperature

    摘要： The stable slurry was prepared by ball-milling with a certain proportion of silica fume as silicon source, glucose as carbon source and metal niobium (Nb) as additives mixed with alcohol water. After the slurry was dried and pulverized, put the powder into a tubular furnace heated to 650℃ for 2h under nitrogen atmosphere to prepare precursor, the heating rate was 5℃ /min. Treated the precursor under vacuum by carbothermal reduction method to prepare silicon carbide (SiC) powder. The effect of temperature and additive content on the morphology of synthesised silicon carbide and the impurity removal order on product purity were explored. After firing at 1300℃, 1400℃, 1500℃ for 2 h, the 3C-SiC powders are detected, and as the temperature increased, the crystallinity of the product become better. When the content of the additive is 1% of the quality of the silica fume, the particle size of the silicon carbide synthesized at the temperature of 1500℃ is even and the dispersion is better. As for the impurity removal order, removed SiO2 first, then removed C can effectively remove the impurities in the product.

    关键词： metal niobium,carbothermal reduction,silica fume,glucose,SiC powders,low temperature

    更新于2025-09-23 15:19:57