塑性形变p型GaAs中的缺陷特性研究

用正电子湮没寿命谱研究了塑性形变P型砷化镓中的缺陷性质．样品原始载流子浓度为2．63X10~18cm-3．形变量分别为2．5％，5％，7．5％，10％和15％．室温正电子寿命测量结果显示，形变样品中有新的空位型缺陷产生，鉴定为空位团．根据塑性形变样品中空位团的正电子捕获率的大小和寿命谱温度关系初步判断：在P型GaAs中，塑性形变产生的空位团的荷电性为正．正电子寿命温度实验显示，在低温下形变样品中还存在正电子浅捕获态．浅捕获中心很可能是锌代位杂质和镓反位缺陷．

DEFECT PROPERTY STUDY IN PLASTIC DEFORMED P-GaAS

Positron lifetime experiments have been performed in plastic deformed and undeformed Zndoped p--type GaAs with a carrier concentration of 2. 63 X 10" cm--3to investigate deformation induced pointdefects. In deformed p--GaAs smaples with strain between 2. 5% and 15%,the results of positron annihilation lifetime measurement at room temperature show that the positron average lifetime increases with theincreasing strains,new vacancy--type defect was formed and identified as vacancy cluster. It can be confirmed that the vacancy clusters are positively charged according to the value of the positron trapping ratesof vacancy cluster and the positron lifetime temperature dependence. At lower temperature, positrons detected negative ions as positron shallow traps. The negetively charged acceptor impurities (Zn) and GaA.antisite should be responsible for the shallow traps maily.