分子束外延P型Hg_(1-x)Cd_xTe少子寿命的研究

Minority Carrier Lifetime in P-type Hg_(1-x)Cd_xTe Grown by MBE

本文利用μ-PCD载流子寿命测量系统,对采用MBE方法生长的Hg空位型中波HgCdTe P型材料和原位As掺杂激活中波P型材料的少子寿命进行了测量,并对材料的少子寿命与温度、载流子浓度的依赖关系进行了研究。结果发现,Hg空位型HgCdTe材料,在非本征区范围内,SRH再结合机制起主要作用;在本征区域,Auger再结合和Radiative再结合机制起主要作用。通过拟和得到,低温下作为SRH再结合中心的汞空位能级位置在离价带顶30meV处,有着类受主的性质,起库仑吸引作用,限制了材料的少子寿命。As掺杂P型材料的少子寿命与同载流子浓度Hg空位为主的P型材料少子寿命相比,大了一个数量级。这就决定了As掺杂P型材料制成的红外探测器件比Hg空位P型材料的探测率高,因此这种材料更适合做多色红外焦平面列阵探测器。

In this work, the lifetimes of P-type Hg-vacancy were compared with the in-situ As-doped HgCdTe. Their relationships with temperature and concentration were also investigated. By fitting the experiment data,it was proved that,for Hg-vacancy HgCdTe, SRH recombination mechanism confines the lifetime in the non-intrinsic region. It shows that Hg vacancies act as SRH recombination trapping center, which locate at the energy level about 30meV above the valence band. On the contrary, in the intrinsic region, auger recombination and radiative recombination mechanism confine the lifetime. For the same concentration, the minority carrier lifetime of P-type As-doped HgCdTe is one magnitude larger than the Hg-vacancy. Actived As-doped material shows higher performance than the Hg-vacancy material, which have much more advantages to the manufacture of multi-color IR devices.