Structural and Optical Properties of SiOx Films Deposited by HFCVD

Room-temperature photoluminescence (PL) of non-stoichiometric silicon oxide (SiOx, x<2) films prepared by hot filament chemical vapour deposition (HFCVD) technique was studied. The effect of the growth temperature was analyzed. These films show a wide and intense visible PL. A wavelength-shift of the absorption edge and an increasing of the energy band gap were observed when the substrate temperature was decreased. High resolution transmission electron microscopy (HRTEM) and X-ray diffraction (XRD) showed the existence of Si nanocrystals (Si-ncs) with diameters between 1 and 6.5 nm within of the SiOx films. The luminescence in these SiOx films is explained according to the combination of different mechanism.