Thermoluminescence Governed by Simultaneous Thermal Stimulation of Electrons and Holes

The possibility of a simultaneous thermal release of electrons and holes in the thermoluminescence (TL) process was suggested in the early stages of the development of this discipline. However, most investigators utilized a model in which carriers of only one kind are thermally released from their “traps”. In this model these carriers then radiatively recombine with carriers of opposite charge in “luminescence centers”. This paper presents the results of a theoretical investigation into a more complex model, which allows the thermal release of electrons and holes in the same temperature range. The solution of a set of four simultaneous differential equations is required in this investigation. The equations are not amenable to analytical solution, so the equations are solved numerically for given values of the model parameters. Conclusions are drawn about the shapes of the TL curves, and the expected stability of the corresponding traps at given temperatures, and the apparent effective parameters namely, the activation energy, the frequency factor, and the order of kinetics, are obtained using the “general order” formalism. In all cases examined, there is a good three parameter fit to the TL peak generated by the examined model. This shows that even a rather general TL peak can be described quite accurately by the three parameter model. The activation energy determined using the three parameter analysis is found to agree rather well with the input activation energy of trapped electrons which is used in the original peak generation for the particular cases examined. In cases where the activation energy for holes is small, the glow peaks occur at relatively low temperatures, and are characterized by a very high effective frequency factor in the three parameter analysis. Furthermore, several cases are studied in which the calculated kinetics order is found to be less than 1.0. Copyright © 1984 WILEY‐VCH Verlag GmbH & Co. KGa