DESIGN OF A THIN-FILM CDTE SOLAR-CELL

Cadmium telluride was originally considered for thin film solar cells because of its optimum band gap, high optical absorption coefficient and ability to be doped. It is a stable compound which can be produced by a variety of methods from stable raw materials. As thin film photovoltaics mature, however, several more subtle attributes have a significant impact on the viability of commercialization. We discuss the observations which have provided insight and direction to Ametek's CdTe solar cell program. Rather than try to modify the inherent material properties of CdTe, advances have been made by designing a solar cell that exploits existing properties. Specifically, the tendency to self-compensate, which makes low resistance contacting difficult, is turned into an advantage in the n-i-p configuration; the CdTe provides an intrinsic layer with good carrier collection efficiency.