AlGaAs∶Sn中DX中心电子俘获势垒的精细结构

采用定电容电压法,测量了n型Al026Ga074As∶Sn中DX中心电子热俘获瞬态,以及不同俘获时间后的电子热发射瞬态;并对瞬态数据进行数值Laplace变换,得到其Laplace缺陷谱(LDS).通过分析LDS谱,确定了电子热俘获和热发射LDS谱之间的对应关系,从而得到热俘获系数对温度依赖关系,以及与Sn相关的DX中心部分电子热俘获势垒的精细结构;通过第一原理赝势法计算表明,Sn附近的AlGa原子的不同配置是电子热俘获势垒精细结构产生的主要原因

Fine structures of electron capture barriers of the DX centers in Sn-doped AlGaAs

Voltage transients due to the thermal electron capture and emission of DX centers in n type Sn doped Al 0.26 Ga 0.74 As were measured by the constant capacitance technique and transformed by Laplace defect spectroscopy (LDS). By analyzing the variations of discrete emission rates with different capture periods, corresponding relations between discrete capture and emission rates and capture coefficients were determined. The fine structures of electron capture barriers of the Sn related DX centers were obtained by linear fitting the data of temperature dependences of the capture coefficients. The results calcuated by using the first principle pseudopotential method show that the fine structures of the capture barriers mainly contribute to Al/Ga at different local configurations near Sn atoms due to the alloy random effect.