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Structural and thermoluminescence (TL) properties of Gd-doped ZnO nanoparticles were investigated in the present study. TL glow curves recorded in the 10-300 K range presented three overlapped peaks around 56, 110 and 155 K for undoped ZnO nanoparticles. The Gd-doping to the ZnO nanoparticles resulted in shift of peak maximum temperatures to lower values and decrease of activation energies associated with the observed peaks. Activation energies of trapping centers were also reported. Taking into account the previously reported studies on defect characterization of ZnO compound, revealed centers were associated with interstitial defects. Structural characteristics of the synthesized nanoparticles were investigated by x-ray diffraction and scanning electron microscopy measurements.

Low-temperature thermoluminescence (TL) properties of ZnO nanoparticles grown by sol-gel method were investigated in the 10-300 K temperature range. TL glow curve obtained at 0.2 K/s constant heating rate exhibited one broad peak around 83 K. The observed peak was analyzed using curve fitting method to determine the activation energies of trapping center(s) responsible for glow curve. Analyses resulted in the presence of three peaks at 55, 85 and 118 K temperatures with activation energies of 12, 30 and 45 meV, respectively. Thermal cleaning process was applied to separate overlapped peaks and get an opportunity to increase the reliability of results obtained from curve fitting method. Heating rate dependence of glow curve was also studied for rates between 0.2 and 0.7 K/s. The shift of the peak maximum temperatures to higher values and decrease in peak height with heating rate were observed. Moreover, X-ray diffraction and scanning electron microscopy were used for structural characterization.

We have carried out thermally stimulated current (TSC) measurements on as-grown Tl2Ga2S3Se layered single crystals in the temperature range 10-60 K with different heating rates of 0.6-1.5 K s(1). The data were analyzed by curve fitting, initial rise, and peak shape methods. The results were in good agreement with each other. Experimental evidence was obtained for trapping center in Tl2Ga2S3Se crystal with activation energy of 11 meV. The capture cross section and concentration of the traps were found to be 1.5 x 10(-23) cm(2) and 1.44 x 10(10) cm(-3), respectively. Analysis of the TSC data at different light excitation temperatures leads to a value of 18 meV/decade for the traps distribution.