Deposition time dependence of the morphology and properties of tin-catalyzed silicon oxide nanowires synthesized by the gas-jet electron beam plasma chemical vapor deposition method

SiOx nanowires (SiOxNWs, x ≤ 2) were grown by gas-jet electron beam plasma chemical vapor deposition method according to the vapor-liquid-solid mechanism at different synthesis times (tdep = 0.5-5 min) using tin particles as a catalyst. Microropes of SiOxNWs were obtained at tdep of more than 1 min. The average growth rate of nanowires was about 19 nm/s. Fourier transform infrared (FTIR) spectroscopy shows that SiOxNWs synthesized at different tdep are very similar in chemical composition (x ≈ 2) and in the bonding network of SiOx. FTIR spectroscopy data on the chemical composition of nanowires are in good agreement with the results of X-ray energy dispersive spectroscopy (EDS) analysis. EDS mapping of silicon and oxygen indicates that the atoms are uniformly distributed in the nanowires. Also, FTIR measurements showed that a significant number of water-adsorbing silanol groups formed on the surface of the nanowires. Photoluminescence spectra of nanowires obtained at different tdep are typical of SiO2 and exhibit a broad band in the region 400-600 nm centered at ~475 nm. The contact angle for SiOxNWs is <21° and decreases to 4.4° with increasing tdep, indicating a superhydrophilic coating.