Preparation of VO2 films via microspacing in-air sublimation method

Abstract

The microspacing in-air sublimation (MAS) is a promising method for single crystals preparation due to its high efficiency and universality. However, this strategy has seldom been reported in other domains, such as film preparation. Vanadium dioxide (VO2) has been widely used in electronics and thermochromic-based applications, which demand simple, efficient, and cheap procedures. This paper reports a new cost-effective and high-efficiency fabrication method of VO2(M) thin films. High-quality VO2 films were prepared on sapphire and mica substrates by combining the MAS method with post-annealing from a precursor of vanadium acetylacetone oxide (VO(acac)2). The VO2/Al2O3 film, even though the thickness is less than 60 nm, shows a relative switching efficiency of 71.31% at 3500 cm−1. The film also exhibits more than three orders of magnitude change in electrical resistance, while the hysteresis of phase transformation was less than 5 °C. This strategy opens a new gate for preparing dense VO2 films with high flatness and high phase change performance without expensive and complex instruments.