Analysis Of Preparation And Properties Of Materials For CdTe Thin Film Solar Cell

CdS thin films were prepared by chemical bath deposition on conductive glass. The pure and Sb-doped CdTe thin films were obtain by vacuum evaporation on substrates of CdS, and were annealed at T=400℃, t=30min with different amounts of CdCl2, The films were etched with a mixture of nitric-phosphoric acid in water. While the pure ZnTe and Y-doped ZnTe films were prepared by double source co-evaporation, the pure CdTe and Sb-doped CdTe thin film solar cells were maked.The characteristics of thin films, such as crystal structure, surface morphology, chemical composition and etc., were tested by X-ray diffraction, atomic force microscopy, X-ray photoelectron spectroscopy and etc.. And the conversion efficiency of the solar cells were tested by solar spectral performance test systems.The experimental results show that, if the deposition time is different, the surface morphology, compactness, surface chemical elements and transmittance of CdS thin films will be different. Ultimately, considering the compactness and transmittance of the films, the deposition time of CdS thin film should be30min. Pure CdTe thin films are cubic structure with [111] preferred orientation. Doping Sb does not change the crystal structure of CdTe thin film, but improves the surface morphology, compactness and uniformity of the grain size. The diffraction peak of Te(101) is observed after etching. CdTe and Sb-doped CdTe thin films have a certain impact with Cl-treat. The effect of pure CdTe films are more obvious on treating with different amounts of CdCl2. After etching, the surface Te-rich phenomenon is different, and the most serious case is use1.0gCdCl2. However, different Cl-treat conditions have little effect on the Sb-doped CdTe thin films.The results of the solar cells efficiency test shows that doping Sb and etching will improve the conversion efficiency of CdS/CdTe solar cells. Meanwhile, the open-circuit voltage and short-circuit current of Sb-doped CdS/CdTe solar cells are both higher than the pure CdTe solar cells, which means doping Sb can reduce the volume resistivity of the CdTe films in order to improve the conversion efficiency.