Comparative study on transport properties of N-, P-, and As-doped SiC nanowires: Calculated based on first principles

According to the one-dimensional quantum state distribution, carrier scattering, and fixed range hopping model, the structural stability and electron transport properties of N-, P-, and As-doped SiC nanowires(N-SiCNWs, P-SiCNWs, and As-SiCNWs) are simulated by using the first principles calculations. The results show that the lattice structure of NSiCNWs is the most stable in the lattice structures of the above three kinds of doped SiCNWs. At room temperature,for unpassivated SiCNWs, the doping effect of P and As are better than that of N. After passivation, the conductivities of all doped SiCNWs increase by approximately two orders of magnitude. The N-SiCNW has the lowest conductivity. In addition, the N-, P-, As-doped SiCNWs before and after passivation have the same conductivity–temperature characteristics,that is, above room temperature, the conductivity values of the doped SiCNWs all increase with temperature increasing.These results contribute to the electronic application of nanodevices.     

电站锅炉中粉煤灰与SiC耐火材料结渣性研究

本文主要研究含Cr2O3的硅酸锆结合SiC耐火材料的抗粉煤灰侵蚀规律,将两种不同的粉煤灰平铺在SiC耐火材料上,作用温度为1250～1450 ℃,保温时间为40小时,然后用视频光学显微镜和XRD衍射图谱来确定其显微结构和物相组成,初步实验结果表明SiC质耐火材料具有较好的抗煤灰侵蚀性能.     

C-V法提取SiC隐埋沟道MOSFET沟道载流子浓度

本文对用C-V法提取SiC隐埋沟道MOSFET沟道载流子浓度的方法进行了理论和实验分析. pn结的存在所造成的埋沟MOS结构C-V曲线的畸变为沟道载流子浓度的提取带来一些问题. SiC/SiO₂界面上界面态的存在也会使提取出的数值与实际数值产生偏差. 本文首先从理论上分别分析了沟道深度和界面态对沟道载流子浓度提取结果的影响，然后对两种沟道深度的埋沟MOS结构C-V曲线进行了测试，提取出了沟道掺杂浓度. 在测试中，采用不同的扫描速率，分析了界面态对提取结果的影响. 理论分析结果和实验测 关键词： C-V法 SiC 隐埋沟道MOSFET 沟道载流子浓度     

HL—1装置SiC涂层辐照实验的表面分析

本文应用表面分析技术研究HL-1装置中SiC涂层的等离子体辐照性能。结果表明,SiC材料应用于孔栏和壁涂层有利于减少杂质和提高等离子体品质。     

The growth of Pd thin films on a 6H-SiC(0 0 0 1) substrate

Pd thin films, grown on Si-rich 6H-SiC(0 0 0 1) substrates, were studied by atomic force microscopy, electron diffraction and high-resolution transmission electron microscopy. It is concluded that the growth is successful only when all the growth process takes place at room temperature. Under these conditions a very good epitaxial growth of Pd is achieved, despite the large misfit (about 8.6%) between Pd and the substrate and the existence of a semi-amorphous layer between the thin film and the substrate. A large number of twins appear in these films.     

Emanation Thermal Analysis of SiC Based Materials

Results of emanation thermal analysis (ETA) characterizing microstructure changes of SiC based materials during heat treatment in argon are demonstrated. This method made it possible to reveal fine changes of the texture of SiC nano-sized powders, SiC micro-sized powders and SiC whiskers under in situconditions of the heating. ETA curves can serve as fingerprints of the respective samples.This revised version was published online in November 2005 with corrections to the Cover Date.     

掺铒a-SixC1-x-H薄膜的发光特性

用等离子体增强化学气相沉积（PECVD）的方法，以固定的氢气（H2）流量和不同的硅烷（SiH4）和甲烷（CH4）流量比沉积了一系列的氢化非晶SiC（a-Si，C1-x-H）膜。用这种宽带隙的a-SixC1-x-H材料作为掺铒的基体材料，通过离子注入的方法得到掺铒的a-SixC1-x-H（a-SixC1-x-H：Er）膜。注入以后的样品经过不同温度的退火。用X射线光电子能谱（XPS）、红外吸收光谱（IR）、拉曼散射谱（Raman）等技术研究不同的SiH4／CH4流量比和退火温度对a-SixC1-x-H：Er发光强度的影响。结果表明，高温退火引起了膜中C的分凝，对饵的发光是不利的。通过低温和室温下铒发光强度的比较，表明这种材料具有较弱的温度猝灭效应。     

Quantitative SIMS analysis of SiC

We performed a systematic study of ion‐implanted 6H‐SiC standards to find the optimal regimes for SIMS analysis. Relative sensitivity factors (RSFs) were acquired for operating conditions typical of practical SIMS applications. The experimental SiC RSFs were compared with those found for silicon: 1 the matrix effect was insignificant in most cases. It was found that the SiO^? cluster ion cannot represent correctly the real oxygen distribution in SiC. The physics of the effect is discussed. Copyright © 2003 John Wiley & Sons, Ltd.     

Synthesis of ultrafine SiC from rice hulls (husks): A plasma process

Heat-treated rice hulls have been used as precursor material for synthesis of ultrafne SiC in a RF plasma reactor. Rice hulls containing finely distributed silica and active carbon act as a source for SiC formation. The plasma-synthesized powder contained ultrafnc -SiC with excess carbon and some unreacted silica. Post-treatment processes such as oxidation and acid (HF) treatment appear to be effective in removing the excess carbon and silica.     

Silicon carbide nanotubes and nanotubular fibers: Synthesis, stability, structure, and classification

Published data on silicon carbide nanotubes (SiC-NT) are analyzed. According to theoretical calculations, single-layer SiC-NTs do not dissociate, but they have not yet been detected experimentally. According to the experimental data, metastable SiC-NTs with walls consisting of several layers and nanotube fibers were produced. The optimized structure of single-layer SiC-NTs was calculated by the RHF/6-31G quantum-chemical method. The possibility of obtaining SiC-NTs by gas-phase chemical deposition from methyltrichlorosilane in the temperature range of 800–1000 °C was investigated. Nanofibers and polygrained SiC nanotubes were obtained, but ordinary layer SiC nanotubes were not detected. To remove the inconsistencies it was first proposed to classify the nanotubes according to the structure of their walls, separating all the SiC-NTs into three types: 1) ordinary layer nanotubes with rolled layers, similar to carbon nanotubes; 2) polynanocrystalline nanotubular fibers or nanotubes with walls consisting of linked differently oriented nanograins; 3) monocrystalline synthetic nanotubes with ideal crystalline walls. It was concluded that the ordinary SiC-NTs of the first type are unstable with the exception of one-or two-layer nanotubes; stable SiC-NTs of the first type and SiC-NTs of the third type have not yet been discovered; only nanotubular fibers of the second type were obtained experimentally. __________ Translated from Teoreticheskaya i éksperimental’naya Khimiya, Vol. 42, No. 1, pp. 3–13, January–February, 2006.