Trap characteristics of UV-activated Y3(Al,Ga)5O12:Ce3+ phosphors

This paper reports on the trap characteristics of commercially obtained Y3(Al,Ga)5O12: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 Y3(Al,Ga)5O12:Ce3+ phosphor measured in the temperature range between room temperature (RT) and 250 °C, two TL peaks were observed, a maximum centered around 74 °C and a shoulder at around 163 °C when excited with UV radiation. Varying the UV irradiation (exposure) time or hence absorbed dose and heating rate significantly affected the peak intensity (Im) and peak temperature (Tm) 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 Y3(Al,Ga)5O12:Ce3+ sample were determined by the variable heating rate method, peak shape method and TL Anal Glow Curve Deconvolution (GCD) techniques.