Transparent conducting properties of Mg and Al co-doped ZnO thin films deposited by spray pyrolysis technique

The oxides and their interplay with metals are of central importance in solar energy, solar cells and environmental as well as in technological applications. Doping of Mg and Al into ZnO offers an interesting way to alter various electronic, optical and structural properties. In this work, Mg doped (Zn0.98Al0.02O) films with different Mg concentrations (0, 1, 2, 4 and 6%) were grown by spray pyrolysis technique and characterized by X-ray diffraction (XRD), UV/VIS optical transmission spectroscopy and electrical measurement. XRD analysis of all samples indicates the presence of hexagonal crystal structure with a preferred orientation of the crystallites along the [002] direction perpendicular to the substrate and the absence of any other secondary phase. All samples exhibited interference fringe patterns in the visible region of transmittance spectra with an average transmission of >60% indicating a good optical quality of the deposited films. The optical studies demonstrate also that Mg-doping induces an increase of the band gap energy. The dark electrical resistivity decreases with increasing Mg doping amount due to the increase of the grain size and the low electronegativity of Mg2+ than Zn2+. (C) 2018 Elsevier Ltd. All rights reserved.