Development of p-n heterojunctions based on thin polycrystalline CdSe films

Thin-film solar cells based on the wide-bandgap semiconductor CdSe were prepared and investigated applying two design principles, a MIS structure and a p-n heterojunction. The MIS structure was prepared by depositing an I layer of ZnSe ( approximately=4.5 nm) combined with an ultrathin Cu layer of 0.2 nm and a Au layer ( approximately=7 nm) onto the CdSe film. After a temper process at 130 degrees C the optimal photovoltaic performance was achieved. The p-n heterojunction was prepared by depositing the ZnTe onto the CdSe film at 450 degrees C under high-vacuum conditions. The photovoltaic limit of the MIS system was caused by an insufficient Schottky barrier height >