The large-area CdTe thin film for CdS/CdTe solar cell prepared by physical vapor deposition in medium pressure

Abstract

The Cadmium telluride (CdTe) thin film has been prepared by physical vapor deposition (PVD), the Ar+O2 pressure is about 0.9kPa. This method is a newer technique to deposit CdTe thin film in large area, and the size of the film is 30ÿ40cm2. This method is much different from the close-spaced sublimation (CSS), as the relevance between the source temperature and the substrate temperature is weak, and the gas phase of CdTe is transferred to the substrate by Ar+O2 flow. Through this method, the compact and uniform CdTe film (30ÿ40cm2) has been achieved, and the performances of the CdTe thin film have been determined by transmission spectrum, SEM and XRD. The film is observed to be compact with a good crystallinity, the CdTe is polycrystalline with a cubic structure and a strongly preferred (111) orientation. Using the CdTe thin film (3ÿ5cm2) which is taken from the deposited large-area film, the 14.6% efficiency CdS/CdTe thin film solar cell has been prepared successfully. The structure of the cell is glass/FTO/CdS/CdTe/graphite slurry/Au, short circuit current density (Jsc) of the cell is 26.9mA/cm2, open circuit voltage (Voc) is 823mV, and filling factor (FF) is 66.05%. This technique can be a quite promising method to apply in the industrial production, as it has great prospects in the fabricating of large-area CdTe film.