Epitaxial growth and metal-insulator transition of vanadium oxide thin films with controllable phases

Vanadium oxide thin films with well controlled phases such as rhombohedra V2O3 and monoclinic VO2 were synthesized on Al2O3 (0001) substrates by optimizing the processing parameters of a polymer assisted deposition technique. X-ray diffraction and high-resolution transmission electron microscopy studies revealed that both V2O3 and VO2 films can be well controlled with good epitaxial quality. The temperature dependency of electrical resistivity demonstrated sharp metal-insulator transitions (MITs) for V2O3 and VO2 films. The crystallinity and the strains in the films are believed to play critical roles in determining the MIT properties.