对富碲液相外延As掺杂碲镉汞(HgCdTe)材料的研究发现，其电学性能存在着不稳定性，材料霍尔参数的实验数据与均匀材料的理论计算结果也不能很好的吻合.通过采用剥层变温霍尔测量和二次离子质谱(SIMS)测试对材料纵向均匀性进行检测的结果显示，外延材料中的As在高温富汞激活退火过程中具有向材料表面扩散的效应，导致在表面形成了高于主体层浓度1~2个量级的高浓度表面层，并导致了AsTe受主的浓度在HgCdTe薄膜中呈非均匀分布.考虑这一效应并采用双层模型的霍尔参数计算方法后，As掺杂HgCdTe液相外延材料的电学行为得到了较好的解释，并较为准确地获得了退火后材料表面层与主体层的受主浓度及受主能级等电学参数.

The properties of As-doped HgCdTe epilayers grown by Te-rich LPE were investigated. The Hall measurements showed that the electrical parameters varied greatly with the samples even though they were grown under the same conditions. If the epilayers are assumed homogeneous, Hall parameters cannot be interpreted well theoretically. By using the secondary ion mass spectrometry (SIMS) and temperature dependent Hall measurements, the accumulation of arsenic atoms was observed on the surface of the HgCdTe epilayers after the Hg-rich activation annealing at high temperature. The arsenic atom concentration of the accumulation layer is 1~2 orders of magnitude higher than that inside, which introduced a nonuniform distribution of acceptor AsTe in HgCdTe epilayer. Based on the characteristic of arsenic atom distribution, a simplified double layer model was applied to describe the distribution of the acceptor in HgCdTe epilayer. Hall parameters of the epilayers can be explained well by using the above method. The concentration and activation energy of acceptor are obtained.