Study of optical and photoelectric properties of copper oxide films

In this work, the dependence of the phase state, photosensitivity region, band structure, and optical quality of 3D-printed nanostructured copper oxide films on the annealing temperature (Ta) was investigated. It was established that both as-deposited and annealed copper oxide films at Ta ≤ 400 °C have the CuO phase and the films annealed at Ta = 450 °C correspond to the Cu2O phase. A possible mechanism of convertation of two phases is discussed. It was established that the band gap of CuO films, caused by indirect allowed optical transitions, determined by the absorption coefficient first derivative and Tauc methods, corresponds to 1.60 eV and 1.35 eV, respectively. It was established that the optical quality of CuO films is the best at Ta = 350 °C. The obtained results open the way to obtain a material suitable for modern optoelectronic applications, in particular, for the development of environmentally friendly solar cells. •The photosensitivity of the films covers the spectral region (1.2–4.0) eV.•Phase conversion from CuO to Cu2O was observed at Ta = 450 °C.•The band gaps of copper oxide films of both phases were determined.•The optical quality of CuO films is the best at Ta = 350 °C.