High-efficiency Cu2O-based heterojunction solar cells fabricated on thermally oxidized copper sheets

Low cost Al-doped ZnO (AZO)/non-doped ZnO (ZO)/Cu₂O heterojunction solar cells with a high conversion efficiency of 4.04% were fabricated by depositing transparent conducting AZO and ZO thin films on high quality Cu₂O sheets prepared by thermally oxidizing copper sheets. To achieve higher efficiencies, it is necessary to form the AZO and ZO thin films at a low deposition temperature using a low-damage deposition method. The best ZO thin-film layer was prepared with a thickness around 50 nm on non-intentionally heated Cu₂O sheets by a pulsed laser deposition.