SYNTHESIS OF Mg-DOPED n(ZnO) THIN FILMS USING SOL-GEL 6 DIP-COATING METHOD AND CHARACTERIZATION OF ITS STRUCTURAL AND OPTICAL PROPERTIES

Abstract

Mg-doped ZnO alloy thin films having hexagonal Wurtzite structures were prepared using the Sol-Gel method. The doping results into, increased surface roughness and reduced grain size. Photonic applications are made easier by altering the optical bandgap of ZnO nano-structured thin films doped with various components. Mg metal atom doped ZnO films are an excellent example for study. In this work, the thin film of Mg-doped ZnO is formed on glass substrate via dip coating method with varied concentration of dopant. Dip-coating method is one of the cheapest methods. SEM, Raman spectroscopy and UV-vis spectroscopy are used to characterize the thin films. The spectroscopic analysis revealed a more uniformed crystalline nano-structured surface with fewer structural deffects. As the Mg atom concentration is increased, the results show a linear increment in the band gap of Mg-doped ZnO thin film in comparsion to the pure ZnO nanostructured thin film, as well as there occurs an improvement in crystalline character. The reduction in intensity of visible radiation (enhancement in radiation in UV region) with increase in Mg concentration indicates for a decrease in intrinsic defects. The changing trends in optical and structural parameters as with increased Mg content reveal a nonlinear and non-monotonic relations. The work provides insights to analyse the dependence of optical bandgap on crystal structure and defects.