The photovoltaic mechanism in CdS/Cu2S heterojunctions

The current-voltage characteristics of a CdS/Cu2S solar cell is explained in terms of the contributing physical effects: Minority carrier generation, recombination, and diffusion in Cu2S, a Schottky barrier layer with sliding boundary condition, nx=0(j), at the junction interface for applied voltages near Vocand current saturation due to high field domains at voltages below Voc-VDlimiting the currents to values below the saturation current in the Cu2S. Conditions are given for lifting this current ceiling. The model shows substantially improved agreement with the experiment than the previously used diode model.