Photoconductive effects in CdS-Cu2S photovoltaic cells

Photovoltaic cells have been prepared by forming layers of Cu 2 S on single crystals of CdS. Undoped crystals with both high and low resistivity have been used, as have low-resistivity samples containing grown-in copper. A study of the spectral dependence of the open circuit voltage, and of the current-voltage characteristics, after baking in air at 200 degrees C, shows that the maximum spectral sensitivity of the cells in the range 0.6-0.7 mu m is associated with a photoconductive region in the cadmium sulphide produced by a diffusion of copper into the cadmium sulphide. The effects of forming the cuprous sulphide layers on basal planes of opposite polarity have also been investigated.