Atmospheric growth and strong visible luminescence of anatase titanium oxide films with various orientations†
At atmospheric pressure, anatase TiO2 films with various nano-morphologies have been grown on quartz substrate by non-thermal TiCl4–O2–Ar reactive plasma vapor deposition. High concentration of oxygen vacancies and undercoordinated Ti atoms are incorporated into the crystal lattice of the deposited films, which can be tuned by changing the discharge conditions such as temperature and vapor flow rate. Strong visible luminescence is found for the deposited films, originating from the radiative recombination of trapped electrons due to uncoordinated Ti atoms and oxygen vacancies. To clarify the growth mechanism, an analytical model is proposed to explain the corresponding discharging process. We find the theoretical predictions agree well with experimental results. By effectively adjusting the morphology and lattice crystallinity, we believe this work can provide an expedient and controllable way to fabricate anatase films with interesting optical properties, which can meet the demands of complex practical situations to the maximum degree.