Phase engineering of vanadium oxide thin films enabled by oxygen pressure control and vacuum annealing

Vanadium oxides are known for a large diversity of crystalline phases with different interesting physical and chemical properties and a wide range of applications. However, due to the close stoichiometric composition of these phases, the growth parameters should be carefully adjusted for each VOx phase. In this work, we propose a method of vanadium oxide thin films phase engineering: growth of amorphous VOx in an oxygen atmosphere at room temperature, followed by vacuum annealing. Our method enables target synthesis of VO2, V4O9, V3O7, and V2O5 phases. A desired phase in a polycrystalline thin-film form can be obtained by finely tuning oxygen pressure during room temperature deposition while keeping other parameters constant. The synthesized thin films can be utilized for various applications: neuromorphic hardware, supercapacitors, sensors, and catalysis.