Heterojunction solar cells on cuprous oxide

Abstract Heterojunction solar cells were made on Cu 2 O by sputtering In 2 O 3 , SnO 2 , CdO and mixtures of CdO and SnO 2 and by thermal evaporation of ZnSe. Photovoltaic effects were observed in most cases. High series resistances were an indication of chemical reactions at the interface. Auger surface analysis showed evidence of copper metal at the interface, arising from chemical reactions. For a CdO/Cu 2 O junction formed at room temperature, no copper metal was found at the interface. The CdO/Cu 2 O cells showed V oc = 0.4 V and I sc = 2 mA cm −2 . The properties appear to be dominated by a multiple-step tunneling at the junction, presumably due to dislocations and impurities in the Cu 2 O samples as prepared.