半导体材料特性和参数研究

提出超晶格(AlAs/GaAs)和应变超晶格（Gex-Si,InxGa1-xAs/GaAs)光伏效应的机理，测量了不同温度下的光伏谱，光伏曲线反映了台阶二维状态密度分布并观察到跃迁峰。计算了导带和价带子带的位置和带宽，根据宇称守恒确定光路迁选择定则，对路迁峰进行指认。研究了光伏随温度变化、激子谱峰半高宽随温度和阱宽的变化，讨论谱峰展宽机制中的声子关联，混晶组分起伏及界面不平整对线宽的影响。测量了元素和化合物半导体单晶材料的室温、低温下的表面光电压谱，推导了有关计算公式，计算得出电学参数（L、n0 、μ、S、W）、深能级和表面能级位置、带隙和化合物组分；分析了电学参数的温度关系；由双能级复合理论，研究了少子扩散长度与深能级关系，计算了深能级浓度和参数。在不同条件下研制了二氧化锡/多孔硅/硅（SnO2/PS/Si)和二氧化锡/硅（SnO2/Si)，测量了它们的光伏谱，分析表明它们存在着异质结。当样品吸附还原性气体（H2、CO、液化石油气）时，光电压有明显变化，因此可做为一种新的敏感元件。分析了它们的吸附机理，计算了有关参数。

Study of the Characteristic and Parameters of Semiconductor Material

The mechanism of the photovokaic effect for superlattices(AlAs/GaAs) and strained uperlattices(GexSi1x/Si,InxGa1-xAs/GaAs)are discussed. The photovoltage spectra at different temperatures have been measured. The curves of SPV reflect the step-like distribution of two-dimensional state density, and transition peaks have been observed. The levels and bandwidths of the subbands have been calculated. The transition speaks are assingned according to the selection rule for optical transition based on the conservation law of parit. The changed in photovoltage with temperature, the full width of half maxium of the transition peaks as a function of temperature and well width for different samples are investigated. The influences of exciton-phonon coupling, alloy disorder and interface roughness on the broading mechanism of the transition peaks are discussed. The surface photovoltage of element and compounds single crystal semiconductors are measured at room and low temperatures. Some calculation formules are derived. The electrical parameters ( L ,n0, μ, S, W ), deep levels and surface level, energy gap and composition of the compounds are determined. The temperature dependence of the electrical parameters are analyzed. The dependence of minority carrier diffusion length on deep level are studied by doublelevel recombination theory. The concentration and parameters of deep levels are calculated. Tin Oxide/Porous Silicon/Silicon(SnO2/PS/Si)and Tin Oxide/Silicon are fabricated at different conditions. The photovoltage spectra of SnO2/PS/Si and SnO2/Si have been studied. It is shown that there exist heterojunctions in SnO2/PS/Si and SnO2/Si. The photovoltage changes evidently when the sample absorbes reducing gas (H2,CO,liguified petroleum). The experimental results indicate that SnO2/PS/Si or SnO2/Si is a good material for gas sensor. The mechamism for the gas absorption of SnO2/PS/Si and SnO2/Si are discussed. The parameters are calculated.