Unraveling Trapping Defects Distribution using Thermoluminescence in Gamma‐Irradiated SrZnO2:Dy Nanophosphors

Abstract

Thermoluminescence (TL) analysis of gamma‐irradiated SrZnO2:Dy nanophosphors elucidates the presence of various trapping centers in forbidden band. Raman and Fourier‐transformed infrared spectra indicate effect on vibrational structure upon doping. Complex glow curves are obtained at varying gamma radiation doses, exhibiting glow features in low (50–180 °C) and high (220–400 °C) temperature regions. The deconvolution of glow curves indicates the presence of TL peaks at ≈100, 143, 202, 269, and 337 °C. The effect of Dy doping is observed as emergence of new glow feature at ≈143 °C. The substitution of trivalent Dy into SrZnO2 host having divalent cations is proposed to be creating (X = Sr, Zn) electron traps and hole traps, along with hitherto existing intrinsic defects. The concentration quenching of TL signal is perceived at 3 mol% Dy doping, whereas comparing glow curves for all samples at saturation dose indicate quenching of low‐ and high‐temperature glow features at different doping concentrations. The theoretical track interaction model and empirical three trap one recombination center (3T1R) model is used to explain former and latter effects, respectively. A schematic band model is proposed to predict the trap distribution upon Dy inclusion, responsible for observed TL in SrZnO2:Dy nanophosphors.