Preparation and Characterization of Thin Copper Sulfide Films for their Application in Solar Cells

Abstract

<p> Two methods for preparing semiconductor grade copper sulfide films, to be used in low cost thin film solar cells,have been investigated. The sulfurization method involves the controlled chemical conversion of copper films into the desired copper sulfide phase. The other method of evaporating Cu2S pellets is more adaptable for an all evaporated thin film solar cell. The copper sulfide films obtained by these methods were characterized using x-rays, cathodoluminescence, electrical and optical methods. The use of optical method in monitoring the stoichiometry of thin copper sulfide films has been illustrated. The photovoltaic properties of thin copper sulfide films obtained by these methods, were also investigated using Cu2S - Si heterojunctions. The behaviour of these junctions indicates that 900 Ȧ thick copper sulfide film is required for optimum photovoltaic conversion. This result may be of some importance in Cu2S - CdS solar cells in further reducing their thickness. Cu2S - Si heterojunctions can also be used to monitor the properties of copper sulfide, as silicon is a well characterized substrate.</p>