掺杂的a-Si_(1-x)C_x:H膜的LESR研究

本文系统地研究了77K下掺杂(B或P)的a-Si_(1-x)C_x:H膜在平衡状态和弱光照下的ESR 特性,文中报道了该膜价带尾态中定域化空穴的ESR吸收谱。实验结果还表明:虽然a-Si_(1-x)C_x:H膜中由于B掺杂会引起光电导的改善,但却不能使悬挂键总浓度减小。     

Optical properties of hexagonal boron nitride thin films deposited by radio frequency bias magnetron sputtering

The optical properties of hexagonal boron nitride (h-BN) thin films were studied in this paper. The films were characterized by Fourier transform infrared spectroscopy, UV--visible transmittance and reflection spectra. h-BN thin films with a wide optical band gap E_g (5.86 eV for the as-deposited film and 5.97 eV for the annealed film) approaching h-BN single crystal were successfully prepared by radio frequency (RF) bias magnetron sputtering and post-deposition annealing at 970~K. The optical absorption behaviour of h-BN films accords with the typical optical absorption characteristics of amorphous materials when fitting is made by the Urbach tail model. The annealed film shows satisfactory structure stability. However, high temperature still has a significant effect on the optical absorption properties, refractive index n, and optical conductivity σ of h-BN thin films. The blue-shift of the optical absorption edge and the increase of E_g probably result from stress relaxation in the film under high temperatures. In addition, it is found that the refractive index clearly exhibits different trends in the visible and ultraviolet regions. Previous calculational results of optical conductivity of h-BN films are confirmed in our experimental results.     

MWECR CVD法高速沉积α-Si:H薄膜的红外光谱研究

应用微波电子回旋共振化学气相沉积(MWECR CVD)方法,在较高速度下沉积了α-Si:H薄膜,用FTIR红外谱仪研究了α-Si:H薄膜的结构特性随H2/SiH4、沉积温度和沉积速率变化关系,并对2000cm-1附近的特征吸收峰用高斯函数进行了拟合分析,获得了沉积高质量α-Si:H薄膜的最佳工艺条件.     

BC_2N薄膜的柱状生长及生长机理

应用热丝辅助等离子体化学气相沉积法 (CVD)合成了表面呈柱状的BC2 N薄膜 ,X射线、红外及X射线电子能谱分析表明 ,薄膜的化学组分主要为BC2 N ,B ,C和N原子间互相结合成键 .扫描电镜观察到 ,薄膜表面形貌呈排列整齐、取向一致的柱体 ,并且发现这种生长方式与沉积参数密切相关 .最后从结合能方面讨论了柱状BC2 N的生长机理 .     

在中考数学复习中培养学生的洞察力

中考数学二轮复习以专题复习为主线,使学生在系统掌握基础知识和基本技能的基础上形成基本的数学思想方法,使之达到系统化、结构化、完整化,进而掌握通性、通法,进一步提高学生分析问题和解决问题的能力.中考数学复习方法多样,模式     

Z箍缩等离子体K壳层X射线自辐射单色成像

采用针孔配接对数螺线柱面晶体方案,研制了一种小型、靶室内置X射线单色成像器,用于获取Z箍缩等离子体K壳层自辐射单色图像。在阳加速器上对该成像器进行了测试,成功地获取了铝丝阵负载Z箍缩等离子体K壳层自辐射的类氢线与类氦线单色图像。实验结果表明:该成像器具有优异的单色性（能谱带宽小于1 eV）,适合于中低原子序数Z箍缩内爆负载的特征谱线单色图像诊断。     

基于分类映射的真三维显示深度抗锯齿算法

针对现有的多层抗锯齿技术在成像深度方向陡峭的三维(3D)图像时出现深度不连续的问题,提出了一种基于分类映射的真三维深度抗锯齿算法。鉴于固态体积式真三维成像是三维曲面的特点,通过分析YOZ(或XOZ)平面截取三维曲面所生成的二维曲线,提出了符合人类立体视觉特性的、基于相邻多层映射的体素分解方法,以及体素映射类型的判定算法。通过原始体素的自适应分类映射,可以在一定程度上扩大深度连续条件下的偏轴观看角度。在搭建的固态体积式真三维立体显示系统上测试三维成像,在较大的偏轴观看角度(约45°)下多数三维成像在深度方向过渡平滑,可以获得较好的深度连续性。     

HW-MWECR-CVD法制备氢化微晶硅薄膜及其微结构研究

用热丝辅助微波电子回旋共振化学气相沉积方法制备出高晶化体积分数的氢化微晶硅(μc-Si:H)薄膜.拉曼散射和X射线衍射技术对样品的微观结构测量分析表明，当反应气体中SiH₄浓度在3.6%—50%之间大范围变化时，μc-Si:H薄膜均具有高的晶化体积分数.进一步的分析表明，在SiH₄浓度较大时制备的薄膜，其结构以非晶-微晶的过渡相为主.薄膜易于晶化或生长为过渡相的主要原因是微波电子回旋共振使SiH₄气体高度分解，等离子体高度电离. 关键词： 微波电子回旋共振化学气相沉积 氢化微晶硅薄膜 拉曼散射 X射线衍射     

非晶半导体基本理论及目前发展概况

非晶态半导体是一门发展极为迅速的新兴学科,是凝聚态物理学中最为活跃的领域之二,已成为材料学科的一个组成部分。大量的事实说明,研究非晶态半导体的意义不仅在技术上能够产生新材料和新器件,而且对于认识固体理论中的许多基本问题也会产     

INVESTIGATION OF GROWTH CHARACTERISTICS OF MONOCRYSTALLINE C60 FILMS IN HELIUM GAS ENVIRONMENT

The growth characteristics of C₆₀ films were investigated in helium gas environment at pressures of 0, 2.667×10^-2 and 6.667×10^-2 Pa, respectively. X-ray diffraction results showed that perfectly (111) oriented monocrystalline C₆₀ films with large grains were successfully deposited on synthetic 1M phlogopite mica-fluorophlogopite (0Ol) plane at a substrate temperature of 160℃ when the helium gas pressure is 2.667×10^-2 Pa. The results indicated that under appropriate helium gas pressure, the energy change of C₆₀ molecules through collisions with helium atoms, and the decrease of the supersaturation of the vapor pressure in the vicinity of the substrate resulted in a quasi-thermodynamic equilibrium deposition system. As a result, well-structured monocrystalline C₆₀ films were deposited on (001) plane of the fluorophlogopite substrate.