Modulation of optical and photoluminescence properties of ZnO thin films by Mg dopant

Nanostructured Zn_1−xMg_xO (x = 0–0.04) thin films were deposited on a glass substrate through the sol–gel dip coating. X-ray diffraction indicates the films exhibited a hexagonal wurtzite structure with maximum intensity at (1 0 1) plane. The intensity of the diffraction peak decreased with increasing the Mg doping concentration. The crystallite size varied as a function of the increase in Mg doping concentration. The deposits showed a nanograin structure for pure ZnO, which changes in the presence of Mg content, and elemental composition was confirmed by using energy-dispersive spectra. Optical analysis showed a significant increase in transmittance from 80 to 90% in the visible range and a decrement in the optical bandgap energy from 3.305 to 3.261 eV with an increase in Mg doping. Photoluminescence spectra showed there was a quenching of near band edge emission with doping concentration and a red emission for Zn_0.96Mg_0.04O film. The color coordinates of the deposits were in the nearly white light region, showing the maximal white light emission.