Hg_(1-x)Cd_xTe n^+-p光电二极管中的深能级及其电流机构的流体静压力研究

HYDROSTATIC PRESSURE STUDIES OF DEEP LEVELS AND RELATED CURRENT MECHANISMS IN Hg_(1-x)Cd_xTe n^+-P PHOTODIODES

在流体静压力(0—2GPa)下,对Hg_(1-x)Cd_xTe n^+-p光电二极管(x=0.5)室温电学特性进行了实验和理论研究。通过考虑深能级压力效应及其对深能级辅助隧道电流的影响,较好地解释了实验上观察到的p-n结伏安特性在小偏压范围下呈现的“反常”压力关系。由对实验数据的理论拟合得到两个深能级:D_l(=E_v+0.75E_g)和D_l(=E_v+0.5E_g),以及相应的电子寿命和空穴寿命,并得到了未掺杂Hg_(1-x)Cd_xTe中深能级的压力系数。

Theoretical and experimental studies have been made about the electrical characteristics of Hg_(1-x)CdxTe n+-p photodiodes with x=0.5 at room temperature and at hydrostatic pressures up to 2GPa. The observed 'anomalous' pressure dependence of the current-voltage characteristics of p-n junctions, which exhibits in the small bias region, has been satisfactorily explained using a theory which takes into account the pressure dependence of deep levels and its effect on deep level-assisted tunneling current. By fitting the dark current to this theory, two deep levels, D_1(=E_v + 0.75E_g) and D_2( = Ev+0.5E_g), as well as their respective electron and hole lifetimes, were obtained. The pressure coefficients of deep levels in undoped Hg_(1-x) Cd_x Te were also obtained.