Trap characteristics of UV-activated Y-3(Al,Ga)(5)O-12:Ce3+ phosphors

摘要

This paper reports on the trap characteristics of commercially obtained Y-3(Al,Ga)(5)O-12:Ce3+ phosphor powder. The effects of UV irradiation time and different heating rates have been discussed using different thermoluminescence (TL) techniques. In the TL glow curves of the Y-3(Al,Ga)(5)O-12:Ce3+ phosphor measured in the temperature range between room temperature (RT) and 250 degrees C, two TL peaks were observed, a maximum centered around 74 degrees C and a shoulder at around 163 degrees C when excited with UV radiation. Varying the UV irradiation (exposure) time or hence absorbed dose and heating rate significantly affected the peak intensity (I-m) and peak temperature (T-m) of the glow curve. The UV exposure time was varied from 3 min to 20 min and we noted that the TL intensity increased with UV exposure time in the range 3-15 min. This may be explained on the basis of second order recombination kinetics taking place due to a re-trapping process of the excitation. The intensity of the two TL peaks moved to the higher temperature side with an increase in the heating rate. The kinetic parameters at various heating rates namely activation energy (E), order of kinetics (b) and frequency factor (s) of the Y-3(Al,Ga)(5)O-12:Ce3+ sample were determined by the variable heating rate method, peak shape method and TL Anal Glow Curve Deconvolution (GCD) techniques. (C) 2016 Published by Elsevier GmbH.