Effect of oxygen pressure on the structural and optical properties of BaSnO3 films prepared by pulsed laser deposition method.

BaSnO3 thin films were deposited on quartz substrate by pulsed laser deposition technique under different background oxygen pressures and the effects of oxygen pressure on the structural, morphological and optical properties of BaSnO3 thin films are systematically investigated using different characterization techniques. The BaSnO3 films deposited without and with oxygen pressures are polycrystalline in nature with cubic crystalline phase. Moderate oxygen ambience favors enhanced crystallinity of the BaSnO3 films and 0.02 mbar is found to be optimum oxygen pressure for highest crystallinity. The surface morphology of the deposited films was strongly affected by the oxygen pressure in the deposition chamber. A systematic increase of film thickness and decrease of RMS surface roughness is observed with increase in oxygen pressure. XPS analysis reveals that barium is in the + 2 oxidation state and Sn is in the + 4 oxidation state in the film deposited at optimum oxygen pressure of 0.02 mbar. The deposited BaSnO3 films have photoluminescence emissions in the visible region and have high transmittance in the visible and infrared regions. The BaSnO3 films deposited at oxygen ambience shows a blue shift in the optical band gap. The optimized film shows high crystallinity, high value of transmittance and wide band gap energy which indicates its suitability for optoelectronic devices

Effect of RF power on the structural and optical properties of zinc sulfide films.

Zinc sulfide (ZnS) films were prepared via a radio frequency (RF) magnetron sputtering technique using different RF powers (100, 120, 150, and 180 W), and the effects of the RF power on the structural and optical properties of the films were studied using x-ray diffraction, micro-Raman spectroscopy, atomic force microscopy, ultraviolet-visible spectroscopy, spectroscopic ellipsometry, and laser photoluminescence spectroscopy. It was found that the RF power has an important impact on the predominant phase formation and crystallinity of the ZnS films. The film thickness, refractive index, and film to bulk relative density increase systematically with an increase in the RF power. Among the various RF power values investigated, 150 W was optimal for the growth of highly crystalline ZnS films with a predominance of the cubic phase and enhanced photoluminescence emissions

Effect of tungsten doping on the properties of In2O3 films.

Highly crystalline tungsten oxide (WO3)-doped indium oxide (In2O3) films are synthesized at room temperature by the RF magnetron sputtering technique. The structural and morphological properties of the as-deposited films and the films annealed at a temperature of 300°C are investigated in detail. X-ray diffraction analysis reveals the presence of a cubic bixbyite structure with preferred orientation along the (222) plane for both the as-deposited and annealed films. Moderate WO3 doping (1 wt.%) enhances the crystallinity of the as-deposited In2O3 films, whereas the crystallinity of the films systematically decreases with an increase in WO3 doping concentration beyond 1 wt.%. Raman spectral analysis discloses the modes of the cubic bixbyite In2O3 phase in the films. Atomic force microscopy micrographs show a smooth and dense distribution of smaller grains in the films. X-ray photoelectron spectroscopy reveals the existence of W5+ in the doped films. The undoped film is highly oxygen deficient. Variation in the concentration of oxygen vacancy can be associated with the degree of crystallinity of the films

Study on the structural, morphological and optical properties of RF-sputtered dysprosium-doped barium tungstate thin films.

Barium tungstate films with different Dy3+ doping concentrations, namely 0 wt.%, 1 wt.%, 3 wt.% and 5 wt.%, are deposited on cleaned quartz substrate by radio frequency magnetron sputtering technique and the prepared films are annealed at a temperature of 700{deg}C. The structural, morphological and optical properties of the annealed films are studied using techniques such as x-ray diffraction (XRD), micro-Raman spectroscopy, field emission scanning electron microscopy, atomic force microscopy and photoluminescence spectroscopy. XRD analysis shows that all the films are well-crystallized in nature with a monoclinic barium tungstate phase. The presence of characteristic modes of the tungstate group in the Raman spectra supports the formation of the barium tungstate phase in the films. Scanning electron microscopic images of the films present a uniform dense distribution of well-defined grains with different sizes. All the doped films present a broad emission in the 390-500 nm region and its intensity increases up to 3 wt.% and thereafter decreases due to usual concentration quenching