CHARACTERIZATION AND ANNEALING OF CdTe THIN FILM PREPARED BY VAPOR TRANSPORT DEPOSITION

Polycrystalline CdTe thin film preparation for CdTe solar cell devices are typically established as the basis for this market-leading solar cell technology. The effects of substrate temperature and atmosphere of deposition and annealing on polycrystalline CdTe thin film prepared by vapor transport deposition (VTD) have been investigated. In order to analyze CdTe-borosilicate single layer structured, X-ray diffraction (XRD), Photoluminescence (PL) and Raman characteristics have been measured. The results show that increasing of substrate temperature can passivate grain boundary and improve grain integrity effectively. The addition of O2 can promote the integrity of crystallization, but high O2 partial pressure can inhibit grain growth. Annealing in O2 ambience is more advantageous to CdTe thin films on preferred (111) orientation crystal plane. As a result of elevated CdCl2-annealed temperature, the peak intensity at 1.27 eV decreased, because of the decrease of the concentration of structural defects in the Cd sublattice. Annealing at 450 °C has caused the oxides of cadmium and tellurium such as CdO, TeOx and CdTeyOx.