Study Of Back Contact On CdTe Polycrystalline Thin Film Solar Cells

CdTe polycrystalline thin film solar cells have attracted focus in the research of thin film solar cells because of a series of advantages, such as high efficiency, simple fabrication, low cost and feasibility to be industrialized for the last two decades. Chinese government has given an important support to develop this kind of solar cell during the national"Tenth-Five Years"Plan. There are several key technologies that must be solved to prepare high efficiency CdTe solar cells. The back contact technology is one of them. This thesis aims to study the basic properties of back contact materials and their application in CdTe solar cells combining the object of 863 program. The efficiency of 13.38% and the fill factor of over 70% have been demonstrated for a cell fabricated in our laboratory, which is the highest level of CdTe solar cells in China. The creative results obtained in the research are listed below.1. The effects of copper concentration and thermal treatment temperature on the structure,composition and morphology as well as the optical, electrical properties of ZnTe and ZnTe:Cu films have been investigated in detail. The relationship between the abnormal conductivity-temperature curves of ZnTe:Cu films and the optimal annealing temperature has been studied and applied to determine the fabrication parameters of back contacts of CdTe solar cells.2. The effects of substrate temperature, thermal treatment temperature and zinc content on the structure,composition, morphology and optical,electrical...