Cu_2O photovoltaic devices incorporating Zn(O,S) buffer layers
CU_2O is a semiconductor composed of earth — abundant and non-toxic elements that is as a promising photovoltaic material. One of the main issues limiting the efficiency of Cu_2O solar cells is the availability of n-type window layers with an appropriate band offset and low interfacial reactivity. In this work, we show the effect of controlling the interface composition on the device properties of a Cu_2O solar cell incorporating a Zn(O,S) window layer. We demonstrate that deposition of Zn(O,S) at elevated temperature limits formation of ZnSO_4 and increases the current that can be collected from the cell by 54%.