Stability and heating rate dependent metal–insulator transition properties of VO 2 film grown by MBE

High quality VO2 films with various thicknesses were grown on sapphire substrate by molecular beam epitaxy. X-ray diffraction and atomic force microscopy measurements indicated that high quality single phase VO2 films with dense and smooth surface as well as free of cracks were achieved. Via adjusting the thickness of VO2 films, the crystalline quality and the surface morphology of VO2 films are significantly improved. The stability and heating rate dependent metal–insulator transition property were investigated. The decreasing of transition temperature and the degeneracy of the stability of VO2 is mainly due to the surface degradation from air exposure and the interdiffusion between the substrate and VO2 film.