Effect of the Working Pressure and Oxygen Gas Flow Rate on the Fabrication of Single-Phase Ag2O Thin Films

Abstract

Ag2O thin films have been applied in various devices, such as photodetectors, photocatalysts, and gas sensors, because of their excellent thermal stability, strong electrical properties, and stable structures. However, because various phases of silver oxide exist, the fabrication of single-phase Ag2O thin films using a general deposition system is difficult. In this study, Ag2O thin films were deposited on glass substrates at different working pressures and O2 gas flow rates using a facing-target sputtering (FTS) system. After optimizing the working pressure and O2 gas flow rate, the Ag2O thin films were post-annealed at different temperatures ranging from 100 to 400 °C to improve their crystallographic properties. The X-ray diffraction patterns of the as-fabricated Ag2O thin films indicated the presence of a single phase of Ag2O, and the ultraviolet–visible (UV–vis) spectral analysis indicated transmittance of 65% in the visible light region. The optimum working pressure and O2 gas flow rate were determined to be 4 mTorr and 3.4 sccm, respectively. Finally, the effect of the post-annealing temperature on the thin film was investigated; the Ag2O peak had high intensity at 300 °C, suggesting this as the optimum post-annealing temperature.