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.