Light-Induced Changes in a-Si∶H Films Studied by Transient Photoconductivity  

非晶硅薄膜瞬态光电导的光致变化(英文)

作　　者：张世斌[1] 孔光临[1] 徐艳月 王永谦 刁宏伟 廖显伯 

机构地区：[1]中国科学院半导体所表面物理实验室凝聚态物理中心,北京100083

出　　处：《Journal of Semiconductors》2002年第8期794-799,共6页半导体学报（英文版）

基　　金：国家重点基础研究资助项目 ( No.G2 0 0 0 0 2 82 0 1)~~

摘　　要：Light induced changes in a-Si∶H films are investigated by transient photoconductivity.The transient photoconductivity decay data can neither be fit well by common power-law for transient photocurrent in amorphous semiconductors,nor by stretched exponential rule for transient decay from the steady state in photoconductivity.Instead,the data are fit fairly well with a sum of two exponential functions.The results show that the long time decay is governed by deep traps rather than band tail states,and two different traps locating separately at 0.52 and 0.59eV below E _c are responsible for the two exponential functions.They are designated as negatively charged dangling bond D - centers.The light-induced changes in photoconductivity are attributed mainly to the decrease in electron lifetime caused by the increase of recombination centers after light soaking.研究了非晶硅薄膜的瞬态光电导的光致变化情况 .用通常的非晶态半导体的瞬态光电流的乘方规律和稳态光电导的扩展指数规律都不能对试验数据进行很好的拟合 ,而采用两个指数函数相加的形式可以对实验数据进行很好的拟合 .这表明非晶硅薄膜长时间的衰退不是由带尾态决定 ,而是由深的陷阱决定的 .两个指数函数的衰退分别对应于距导带 0 .5 2 e V和 0 .5 9e V的两个陷阱 ,这两个陷阱可以被指认为带隙中的荷负电中心 .光照后 ,带隙中的复合中心增加 ,导致电子寿命的减少 ,从而引起光电导的衰退 .

关 键 词：amorphous silicon transient photoconductivity light-induced change 

分 类 号：TN304.055[电子电信—物理电子学]