Highly transparent and luminescent nanostructured Eu203 doped ZnO films.

Zinc oxide is a wide, direct band gap II-VI oxide semiconductor. Pure and Eu-doped ZnO films are prepared by RF Magnetron sputtering at different doping concentrations (0.5, 1, 3 and 5 wt %). The films are annealed at 500 0C in air for two hours. The structural, morphological and optical properties of the films are characterized using XRD, micro-Raman, AFM, UV-Visible and photoluminescence spectroscopy. The thickness of the films is measured using stylus profilometer. XRD analysis shows that all the films are highly c-axis oriented exhibiting a single peak corresponding to (002) lattice reflection plane of hexagonal wurtzite crystal phase of ZnO. The micro-Raman spectra analysis reveals the presence of E2 high mode in all the samples which is the intrinsic characteristic of hexagonal wurtzite structure of ZnO. The appearance of LO modes indicates the formation of defects such as oxygen vacancies in the films. AFM micrographs show uniform distribution of densely packed grains of size with well defined grain boundaries. All the films exhibit very high transmittance (above 80%) in the visible region with a sharp fundamental absorption edge around 380 nm corresponding to the intrinsic band edge of ZnO. All the films show PL emission in the UV and visible region. Paper presented at the 2nd International Conference on Structural Nano Composites (NANOSTRUC 2014) held 20-21 May 2014 in Madrid, Spain

Highly ordered good crystalline ZnO-doped WO3 thin films suitable for optoelectronic applications.

Highly ordered ZnO-doped WO3 thin films with good crystalline quality are prepared using radio frequency magnetron sputtering technique, and its morphological and structural properties are studied using various characterization tools such as field emission scanning electron microscopy, energy-dispersive x-ray spectroscopy, x-ray diffraction technique, micro-Raman spectroscopy, and x-ray photoelectron spectroscopy. Morphological analysis shows a smooth surface for pure film, whereas the ZnO-doped films presents a dense distribution of grains of larger sizes with well-defined grain boundary. X-ray diffraction studies reveal the enhancement of crystalline quality of the films with increase in ZnO doping concentration up to 5 wt.%, beyond which the crystalline quality gets deteriorated. A phase modification from a single monoclinic WO3 phase to mixed monoclinic WO3 and W18O49 phases is observed for films with higher ZnO doping concentrations

Influence of Pr doping on the structural, morphological, optical, luminescent and non-linear optical properties of RF-sputtered ZnO films.

The effects of Pr doping on the structural, morphological, optical and non-linear optical properties have been investigated. X-ray diffraction and Raman analysis reveals the formation of highly c-axis-oriented films with hexagonal wurtzite structure of ZnO. Atomic force microscopy and scanning electron microscopy images reveal the formation of grains with well-defined grain boundaries. The Pr-doped films present excellent optical transparency in the visible region. The photoluminescence spectra show both UV and visible emissions and the intensity of the visible emission increases with Pr doping. Nonlinear optical properties of the Pr-incorporated ZnO nanostructures have been investigated using the open aperture Z-scan technique. It is interesting to note that 1wt.% praseodymium-incorporated ZnO film shows saturable absorption, whereas the 5wt.% praseodymium-incorporated ZnO shows reverse saturable absorption and the high value of non-linear absorption coefficient (β) for 5wt.% Pr-doped ZnO film suggests the suitability of these films for optoelectronic device applications

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