用改进的调制光电流相移分析技术研究氢化非晶硅的隙态分布  

Gap State Distribution in a-Si: H Studied by Improved Phase-Shift Analysis of Modulated Photocurrent

作　　者：盛殊然[1] 孔光临[1] 廖显伯[1] 夏传钺[1] 郑怀德[1] 

机构地区：[1]中国科学院半导体研究所,北京100083

出　　处：《Journal of Semiconductors》1997年第7期513-517,共5页半导体学报（英文版）

摘　　要：本文提出了一种严格校准调制光电流相移的方法，在此基础上，采用调制光电流相移分析技术研究了不掺杂氢化非晶硅（a-Si：H）薄膜费米能级以上隙态密度及其分布的光致变化效应．实验发现，光电流相移的校准对确定隙态密度及其分布是至关重要的．除了核准测试系统的相移频率特性外，还需考虑样品本身电阻、电容等参数的影响，否则会使隙态密度偏低1～2个数量级；经严格校准的光电流相移测试，a－Si：H的隙态分布在导带边以下约0．43eV处观察到一个峰，可能是双占据悬挂键D-中心引起的．光照引起浅态减少，深态增加，引起了隙态重新分布．A rigorous method of calibrating the phase-shift of modulated photocurrent has been presented. Based on this, the photoinduced change of the density of gap states above the Fermi level in undoped a-Si: H has been investigated by phase-shift analysis of modulated photocurrent. The experimental results show that the phase-shift calibration is very important to the determination of the density of gap states. Apart from the phase-shift frequency-response characteristics of the measuring system, those of the resistance and capacitance of the sample also need considering, or else the density of gap states can be underestimated by 1～2 orders of magnitudel The exactly calibrated measurements of gap states show a peak at about 0. 43eV below the conduction band edge, which may be associated with doubly occupied dangling bonds. After light soaking, the deep states increase, while the shallow states decrease, indicating that illumination does not increase all the gap states, but induces the redistribution of gap states.

关 键 词：氢化非晶硅 调制光电流相移 隙态 非晶态半导体 

分 类 号：TN304.8[电子电信—物理电子学]