Preparation of Chromium Oxide Binary System Thin Films with Adjustable Electrical Resistivity by Changing Oxygen Pressure

Abstract

The binary Cr-O chemical system compounds demonstrate significant developmental prospects in solar cells, microelectronics, photovoltaic devices, and catalysis. Among them, the semiconductors Cr2O3 and CrO3 have garnered considerable interest, partly due to their ease of synthesis. However, Cr2O3 prepared using reactive magnetron sputtering contains transitional Cr-O structures whose physical and chemical properties remain largely unknown due to their variability. In this study, Cr2O3 was directly deposited using reactive magnetron sputtering, and its microstructure and photoelectric properties were characterized. The ratio of process gases is crucial for the performance of the resultant films. By altering the oxygen partial pressure, the oxygen doping changed the concentration of free electrons in the grown material, thus producing a semiconductor with a high band gap of 3.34 eV. When the oxygen partial pressure was adjusted to a certain level, the concentration of oxygen impurities in the material was reduced, directly enhancing the conductivity of chromium oxide by nearly two orders of magnitude. This method of changing the process gases by reducing carrier concentration through oxygen doping provides a potential approach for customizing the photoelectric properties of CrOX, transforming metallic CrO2 into the semiconductor CrO3, and greatly expanding the application range of chromium oxide (CrOX) materials.

Keywords: Reactive magnetron sputtering, Oxygen doping, Chromium oxide thin film, Resistivity and bandgap