CdZnTe晶片表面钝化研究

用NH4F／H2O2对Br2-MeOH抛光CdZnTe晶片表面进行了表面钝化处理，通过I-V测试及XPS分析分别对钝化前后的CZT晶片的电学性能和表面组成进行了表征。I-V测试结果表明NH4F／H2O2对CdZnTe晶片表面有较好的钝化效果，电流下降率随所加偏压的增加而下降。在10V偏压下，电流下降最明显，下降率为73．7％。与欧姆定律发生偏离的临界场强为333V／cm。XPS分析发现，用NH4F／H2O2处理可使CdZnTe表面富集的Te79.28％被氧化成TeO2，氧化层的厚度约为3．15nm。钝化后的表面更接近CdZnTe的化学计量配比。

Surface passivation of CdZnTe wafer

In this paper, CdZnTe wafer was passivated with NH_4F/H_2O_2 solution after the chemical polishing with Br_2-MeOH solution. The electricity property was characterized with I-V measurement and the surface composition was quantitatively measured with XPS analyses. I-V measurement showed that the CZT wafer surface was significantly passivated after the treatment. The dropping rate of current reduced with increasing the bias voltage. At the bias voltage of 10V, the current dropping rate was the highest, about 73.7%. The critical field intensity was about 333V/cm, at which I-V curves began to deviate from ohm law. Through XPS analyses, it was found that about 79.28% of Te in CZT surface layer was oxided to form TeO_2. The depth of oxided layer was about 3.15nm. The composition of passivated surface became more close to the stoichiometric one.