Non-equilibrium alloying controls optoelectronic properties in Cu2O thin films for photovoltaic absorber applications

Cuprous oxide (Cu2O) has recently received much attention as a candidate material for oxide photovoltaics. However, its low absorption coefficient due to the symmetry forbidden band gap and low intrinsic p-type doping level are obstacles for further advancing the performance of Cu2O thin film solar cells. Following computational predictions on the band gap, doping, and optical properties, we report combinatorial synthesis and characterization of Cu2-2xZnxO1-ySey thin film alloys and the associated device modeling results. We show that the absorption and the conductivity can be independently controlled by Se and Zn content, thereby devising a possible route to design of more efficient oxide photovoltaics and tandem solar cells. (C) 2015 AIP Publishing LLC.