Influence of deposition time on the visible-light-driven photocatalytic activity of Cu2O thin films by reactive sputtering at room temperature

Nanocrystalline single-phase Cu2O thin films were deposited on a glass substrate by radio frequency (RF) reactive sputtering at room temperature with various deposition time of 1, 3 and 5 min. Films are in the cubic crystalline phase. Crystallite size increases from 16 to 22 nm and the surface roughness also found to increase from 1.8 to 2.3 nm with deposition time. XPS results denote that the defects in the films at lower deposition time predominantly attributed to oxygen vacancy. Optical band gap is found to decrease from 2.54 to 2.12 eV. The films were subjected to photocatalytic degradation of organic pollutant crystal violet. Cu2O thin films showed an excellent photocatalytic activity under visible light irradiation. Films sputtered at the lowest deposition time of 1 min exhibited higher degradation efficiency of 94%. (c) 2020 Elsevier B.V. All rights reserved.