Fabrication of epitaxial V2O3 thin films on Al2O3 substrates via mist chemical vapor deposition

Abstract

Epitaxial V2O3 films, which undergo a metal–insulator transition at 155 K, exhibit a drastic change in resistivity. Consequently, they are expected to be used in current-driven switching devices and smart switching devices for the protection of superconducting coils. However, conventional fabrication methods for epitaxial V2O3 films require a high vacuum, resulting in high processing costs and low productivity. In this study, we report the fabrication of epitaxial V2O3 films on R-, C-, and A-plane sapphire substrates via mist chemical vapor deposition (mist CVD), which does not require a high vacuum. Consequently, it facilitates the fabrication of thin films at a low cost with high productivity. Deposition at various temperatures reveal that epitaxial V2O3 films can be grown on sapphire substrates, even under atmospheric pressure, and the optimal temperature for epitaxial growth is 823 K. All the films grown at 823 K exhibit a clear metal–insulator transition, demonstrating a drastic change in the resistivity at approximately 155 K. The film on C-plane sapphire exhibits a lower transition temperature (129 K) than those on R- and A-plane sapphire substrates. The fabrication of high quality films via the low cost mist CVD process can enable the mass production of V2O3-based devices.