Direct Solar Energy Conversion for Large Scale Terrestrial Use. The CdS/Cu2S Heterojunction in Steady State.

摘要

The physics of the key processes in the CdS/Cu2S solar cell is discussed. The electron generation and diffusion is analyzed in Cu2S. Collection saturation of electrons from the Cu2S and high-field domains in CdS are proposed to be responsible for current saturation. Proper matching of these is necessary to obtain satisfactory collection efficiencies and characteristics. Matching is achieved by heat treatment yielding sufficient copper doping ('sensitization') in the junction region. The boundary conditions at the junction interface are analyzed and provide additional insight into the carrier transport through a heterojunction. The current-voltage characteristics with optical excitation are discussed as being substantially different from the diode characteristic in the dark.