High-mobility copper (I) oxide thin films prepared by reactive dc magnetron sputtering for photovoltaic applications

Copper (I) oxide (Cu₂O) is considered a promising material for low-cost photovoltaic applications. In this contribution, high-quality Cu₂O films are prepared by reactive dc magnetron sputtering. We optimize deposition parameters to achieve pure Cu₂O-phase thin films. We report the control of electrical, optical, and structural properties of the resulting films by varying the substrate temperature during film growth, and carefully controlling other growth parameters. We achieve a columnar grain structure with the large average grain size (884±373 nm) and high-mobility (62 cm²/V·s) at room temperature. All films exhibit an optical bandgap between 1.9 and 2.0 eV, and the samples grown at high temperature show enhanced optical transmission at wavelengths greater than 600 nm.