Preparation and optical study of APCVD mixed metal oxide films

Mixed metal oxides based on MoO3 and WO3 are prepared by chemical vapor dep osition (CVD) using a precursor-mixture Of MO(CO)(6) and W(CO)(6) powders. By pyrolytical decomposition of the mixed vapors at atmospheric pressure in presence of oxygen, thin films were deposited on silicon substrates at 200 degreesC. The films were characterized by Raman, IR and Ellipsometric Spec troscopies. In as-deposited form the films are amorphous as revealed by Ram an spectra. Post-deposition annealing at 200 and 300 degreesC does not sign ificantly change the vibrational and optical properties. Annealing at 400 a nd 500 degreesC leads to predominantly amorphous structure with appearing o f crystalline phase. The character of the absorption spectra and the values of the optical energy bandgap (2.57-2.66 eV) suggest that the CVD-MoO3-WO3 oxide films have highly defective structure.