Bandgap Engineering of ZnO by Alloying with MgO

Abstract

We report the synthesis and characterization of Mg doped ZnO thin films prepared by pulsed laser deposition method. From the X-ray diffraction studies it was found that the films are nearly epitaxial in nature without any phase segregation up to 25% of Mg doping. The independent measurements from UV-visible and photoluminescence studies confirmed that with increase in Mg concentration the band gap of Zn1-x-MgxO thin film increases systematically. Interestingly with increase in Mg content, the intensity of the peak related to band to band transition decreased drastically where as an opposite trend was observed for the intensity of defect related peak in the photoluminescence spectra. This has been attributed to dominant non-radiative process.