氟系非晶态硅材料的研究

作者用辉光放电方法,基本上按照Ovshinsky等人报道的制备a-Si:F:H合金的工艺条件制得了a-Si:F:H合金薄膜.这种材料的含氢量远比a-Si:H合金材料为低.据初步测试结果,这种材料具有良好的光电导特性和热稳定性.目前,我们正在继续完善有关工作并将做具体报道.还将报道对a-Si:F:H材料用溅射方法制备的有关结果.     

Ⅱ-Ⅵ族化合物(Hg_(1-x)Cd_xTe)非晶薄膜的半导体性质

本文对用蒸发法制备的非晶和多晶碲镉汞(Hg_(1-x)Cd_xTe)薄膜的结构特性及其光学和电学性质进行了研究。在800—2600nm的波长范围内测量了样品的透过率,得到了非晶和多晶状态相应的光学隙分别为1eV以上和0.65eV左右。对非晶样品的退火实验发现,在90—100℃区间退火使非晶样品的结构转变为多晶,同时电阻率突然变小约5个数量级和光学隙由1eV以上突变为0.62eV左右。在20—300K的温度范围内,分别测量了非晶与多晶样品的电阻率,所得结果可用现代非晶半导体理论进行解释。     

PIN结构a-Si∶H电池的光诱导弛豫现象

本文报道了用毫秒方波光脉冲对PIN结构非晶硅电池输出光电流瞬态特性的研究结果。在测得的特性曲线中,起始端出现一个与激发光波长和外加偏压有关的半宽约0.1毫秒的峰状结构。峰的产生和特性可用i层内靠p层一边的空穴积累和n层一边的电子积累解释,峰下积分面积大小可用它们的积累数目多少解释。     

非晶硅电子结构的EHT理论研究

本文用EHT方法对Si_(47)H_(60),原子团的电子态密度性质进行了多种情况下的计算分析,计算结果表明,非晶硅与单晶硅电子态密度谱的区别主要发生在B峰与C峰之间,而不是通常所认为的A峰与B峰之间,这与Hayes的XPS实验结果一致.据我们计算分析,得出产生这一区别的主要原因是键角和二面角无序,而不是以前人们所认为的键角的单一无序.     

硅离子簇的理论研究

本文采用ＭＮＤＯ方法研究了Ｓｉｎ，Ｓｉｎ＋和Ｓｉｎ２＋（ｎ＝２—６）簇的原子结构，得到了一系列稳定的簇结构，并确定出每一类簇所对应的最佳稳定结构．从中发现，无论Ｓｉｎ，Ｓｉｎ＋还是Ｓｉｎ２＋簇，都存在共同的“幻数’，即４，５，６，然而，Ｓｉｎ，Ｓｉｎ＋和Ｓｉｎ２＋对应的稳定结构一般是各不相同的．本文的结构说明，以往人们单纯从中性Ｓｉｎ簇的研究去推断并解释Ｓｉｎ离子族的结构和性质是不恰当的，荷电将改变原子簇的构型．文中还指出了几个以前没有发现的稳定构型．     

Si(113)表面电子结构的研究

采用Si_(16)H_(21)和Si_(31)H_(39)原子集团分别模拟Si(113)和Si(111)表面;通过半经验自洽CNDO法计算了两个体系的电子结构.结果表明,Si(113)具有与Si(111)不同的表面态特征.Si(113)表面台阶和台面原子上电荷重新分布,与悬键相关的表面电子态都强烈地定域在表面Si原子上,尤其局域在悬键方向上,并且具有比(111)面上更高的悬健态密度.理论计算结果能解释以前的光电子谱实验.     

a-Sn膜的半导体性质(英文)

Amorphous Tin(a-Sn) film deposited by vacuum evaporation is reported and its properties are researched in this paper. X-ray diffraction for specimens prepared at lower rate of evaporation and substrate temperature demonstrates that the Sn film has amorphous structure. The temperature dependence of d.c. conductivity of the a-Sn film shows semiconductor properties the measurements of optical absorption made on each specimen, determine the optical gap. This paper interprets the experimental results in terms of theory of Anderson localization and the Mott amorphous semiconductor.     

PIN a-Si:H太阳电池I-V特性光感生的可逆改变(英文)

The light-induced reversible changes in I-V character of PIN a-Si:H solar cells are measured in a similar way to the study of S-W effect for a-Si:H films. It is found that the forward character changes can be explained by the recombination current (m= 2 , I-exp(eV/mKT) mechanism, and the inverse one is dominated by the barrier-layer generation current (IG = eniX0/2τ). The results may be explained by the model for S-W effect recently suggested by Dai Guocai, et al.     

水分子在Si（100）面上吸附位的确定

本文用Ｓｉ６６Ｈ５０原子集团模拟Ｓｉ（１００）表面，采用ＣＮＤＯ分子轨道理论方法计算了Ｈ２Ｏ在其上吸附的势能面．确定出Ｈ２Ｏ在Ｓｉ（１００）表面的最佳吸附位为洞位．在桥位Ⅰ、桥位Ⅱ和顶位上吸附时势能依次升高．     

根据IR吸收谱的a-Si:H结构模型(英文)

Although the presence of hydrogen is necessary to obtain a good quality amorphous silicon, the silicon matrix still remains incomprehensible. A series of crystalline silicon clusters are built with hydrogen saturating dangling bonds on the surf ace. It is found that only two types of hydrogen-rela ted groups (Si-H and Si-H2) are necessary. Furthermore, we have calculated their stretching vibrational frequences using the improved method. The results are consistent very well with conventionally obtained spectra including Si-H at 2000cm-1 and Si-H2 at 2100cm-1 peaks.These interesting results propose a structure model of the a-Si:H, which is neither CRN nor microcrystal, but a largely concentrated silane-like "molecule". This model may be used to understand the proposed doping mechanism of a-Si:H alloys.