Thermoluminescence studies of γ-irradiated ZnO:Mg2+ nanoparticles

Abstract

Pure and Mg2+ doped ZnO nanoparticles are synthesized by solution combustion method. X-ray diffraction studies of the samples confirm hexagonal phase. Crystallite size is calculated using Scherer formula and found to be ∼30nm for undoped ZnO and 34–38nm for Mg2+ doped ZnO. A broad PL emission in the range 400–600nm with peaks at 400, 450, 468, 483, 492, 517, 553nm are observed in both pure and Mg2+ doped nanoparticles. Near band edge emission of ZnO is observed at 400nm. The broad band emissions are due to surface defects. PL emission intensity is found to increase with Mg2+ concentration up to 1.5mol% and then decreases due to concentration quenching. Samples are irradiated with γ-rays in a dose range 0.05–8kGy. Gamma irradiation doesn’t affect PL properties. Undoped samples exhibit unstructured low intense TL glow with peak at 720K. Whereas Mg2+ doped samples exhibit well structured TL glow curves with peak at ∼618K. TL glow peak intensity of Mg2+ doped samples increases with Mg2+ concentration up to 2mol%, thereafter decreases. TL curves of Mg2+ (2mol%) doped ZnO exhibit two glows, a high intense peak at 618K and a weak one with peak at ∼485K. TL intensity of Mg2+ (2mol%) doped ZnO samples increases with gamma dose up to 1kGy and then decreases. Kinetic parameters of TL glows are calculated by deconvolution technique. Activation energy and frequency factor are found to be 1.5eV and 3.38×1011s−1 respectively.