Interdiffusion of CdS and CdTe in screenprinted and sintered CdS-CdTe solar cells

A certain degree of intermixing of CdS and CdTe layers occurs during the preparation of CdS-CdTe solar cells by the screen printing and sintering technique. A study of the interdiffusion was performed for varying production parameters, comprising spectral response and diode behaviour of the cell and optical and crystallographical properties of the window and absorber layers. The interdiffusion is seen to increase with CdTe sintering temperature and with CdCl₂ content in the CdTe layer and is dependent on the CdS base. A poor short-wavelength spectral response and an extended long-wavelength spectral response can be explained in terms of the optical properties of the window and absorber layers, which in turn, are a consequence of the formation of CdS_1-xTe_x and CdTe_1-yS_y solid solution phases