CdTe/CdS thin film solar cells are being investigated extensively these days by many workers as an option for low cost photovoltaic applications . In order to achieve high efficiency solar cell it is important that the CdS film should have minimum possible structural defects and reasonably large grain size. The CdS films for CdTe/ CdS solar cell structure are mostly grown on glass substrates by chemical bath deposition (CBD). Although adherent, transparent and conformal films with index of refraction close to single crystal CdS can be grown by CBD, impurity inclusions and micropinholes are a problem there in. Very little work has been carried out to grow CdS films by thermal evaporation in vacuum. In the present work we have grown pure and CdCl2 doped CdS films on glass substrates by thermal evaporation and carried out microstructural investigations of these films using scanning electron microscopy.
Corning 7059 glass of 25.4 x 25.4 x 1.2 mm size were used as substrates for the deposition of CdS as well as CdCl2 doped CdS films.