Strong influence of substrate temperature on the growth of nanocrystalline MoO3 thin films

Nanocrystalline MoO3 thin films are prepared by electron beam evaporation technique. By using the dry MoO3 pellets, the films are deposited on quartz substrates at substrate temperatures ranging from 100 °C to 400 °C. A phase structure of β-MoO3 at the substrate temperature 200 °C is characterized by X-ray diffraction, but α-MoO3 comes forth at 300 °C and 400 °C. The surface morphology, cross section view and plate form nanostructures have been illustrated from the scanning electron microscope images. The absorption spectra of films show that the energy band EgEg decreases with the increasing substrate temperature, due to the increase in oxygen vacancy. The resistances of thin films prepared at various substrate temperatures gradually decrease with the increasing environmental temperatures.