用光电子能谱研究CdTe太阳电池的背接触特性

CdTe太阳电池的背电极须采用高功函数金属。通过采用光电子能谱(XPS)分析了高功函数金属Au和Ni分别作为背电极的CdTe太阳电池背接触特性，发现在背电极剥离后，Au在ZnTe/ZnTe∶Cu背接触层表面以Au单质形式存在，扩散深度较浅；Ni扩散到ZnTe/ZnTe∶Cu复合层的深度比Au大，且大多呈离子态，与ZnTe/ZnTe∶Cu复合层中的富Te离子形成Ni_xTe，提高了掺杂浓度，使电池性能获得改善。在两样品中还发现，不论是Te的峰还是Zn的峰，其峰的位移变化都很小，说明两样品中Te和Zn的存在形式没有发生变化。

Study on the Back Contact Performances of CdTe Solar Cells by XPS

The metal materials with high work function should be used as the back electrode of CdTe solar cells. In the present paper, the back contact performances of CdTe solar cells with Au film and Ni film, respectively, were studied by X-ray photoelectron spectrum (XPS). After exfoliating the back electrode film, it was found that Au on the surface of ZnTe/ZnTe∶Cu complex back contact layer is in the form of Au atoms and the concentration and depth of Ni diffusing into the ZnTe/ZnTe∶Cu back contact layer are higher than that of Au. What’s more, some Ni changes into Ni+_x ion which leads to rich Te ions in ZnTe/ZnTe∶Cu back contact layer. So the diffusing concentration is increased, which makes the characters of CdTe improved. In the samples, the displacement of either Te or Zn peak position changes little, which indicates that both Te and Zn do not change in the modality.