Mg-doped tailoring of Zinc oxide for UV-photodetection application

Abstract

Pristine and Mg-doped ZnO nanostructure have been synthesized by hydrothermal method, characterized by different techniques and their photo-response has been studied. The X-ray diffraction (XRD) pattern revealed that pure and doped ZnO have hexagonal wurtzite structures. For 7% and 10% Mg doping, an additional signature of MgO is observed, whereas for lesser doping no such additional peak appears in XRD pattern. The crystallite size of the doped sample varies with increasing Mg concentration. Raman spectra also revealed that the synthesized pure and doped ZnO nanoparticles have a wurtzite structure. XPS studies confirm that there is no impurity phase observed for pure and 5% Mg-doped ZnO samples. Field Emission Scanning Electron Microscopy (FESEM) reveals the particle are spherical shape having a particle size between 23 nm to 17 nm with the change of dopant concentration which is also supported by Transmission Electron Microscopy studies (∼16 nm for 5% Mg-doped ZnO). UV–Visible absorbance spectra reveal that the absorption edge is shifted to a lower wavelength after the Mg doping. From photoluminescence studies, it has been found that UV band emission appears around 369 nm and broad-spectrum in 400 nm–600 nm (visible) region. The UV photoresponse studies show that the 5% Mg-doped ZnO has a better photoresponse.