Advances in CuInSe2 and CdTe thin film solar cells (original) (raw)

Research on CuInSe2 and CdTe thin film solar cells is discussed. CuInSe2 was deposited by selenization of Cu/In layers and was used to make a 109/0 efficient CuInSe2/(CdZn)S cell. Characterization of the reaction mechanisms is described. The open-circuit voltage Voc of CuInSe2/(CdZn)S cells is dominated by recombination in the space charge region, so increasing the band gap or decreasing the width of this region should increase Voc. Increasing the band gap with a thin Cu(InGa)Se2 layer at the CuInSe2 surface has demonstrated increased Voc with collection out to the CuInSe2 band gap. A post-deposition treatment and contacting process for evaporated CdS/CdTe cells was developed and high efficiency cells were made. Several steps in the process, including a CdC12 coating, a 400 °C heat treatment, and a contact containing copper are critical. ZnTe films were deposited from an aqueous solution as a contact to CdTe. 0379-6779/91/$3.50