A tunneling model for the decay of luminescence in inorganic phosphors: The case of Zn2SiO4:Mn

Abstract

We have investigated phosphorescence, thermoluminescence, and photostimulated luminescence in manganese activated zinc silicate phosphors, both with and without arsenic doping. Both phosphorescence and photostimulated luminescence intensities are found to decay as the reciprocal of the time, a result which requires a different interpretation from that given by the usual model of electron release from a distribution of trap levels. To account for these results we propose a new model based on the radiative recombination of electrons and holes through tunneling from shallow traps or from excited states of the deeper traps. A simple expression is derived which describes the decay of both types of luminescence in phosphors under very general conditions for which tunneling is the dominant recombination mechanism. Excellent agreement between theory and experiment is found.

Delayed recombination and excited state ionization of the Ce3+ activator in the SrHfO3 host

“…Space correlation (aggregation) of emission centers and charge carrier traps seem to be a rather frequent event in luminescent materials [11]. Furthermore, tunneling-driven radiative recombination has already been considered in the description of classical phosphors some time ago [12] and systematically applied to explain recently studied photo-, radio-and thermo-luminescence characteristics in doped aluminum perovskites, garnets and silicates as well [13].…”

Local, Temperature-Dependent Trapping and Detrapping in the LiGa5O8:Cr Infrared Emitting Persistent Phosphor

“…19 Plotting the inverse of the afterglow intensity against time reveals an approximately linear t −1 behavior for the persistent luminescence ( Figure 2). This specific decay behavior has been linked to either a detrapping mechanism from isolated traps via tunneling processes; 21 or an indication for the presence of a broad trap distribution in the phosphor. 23,24,27,28 In general, one can distinguish between the two processes by checking the temperature dependence of the afterglow and thermoluminescence behavior.…”

“…behavior, which has been linked to either a tunneling mechanism [20][21][22] or a thermally activated detrapping process from a broad distribution of traps in the host. [23][24][25] Via a combination of afterglow and thermoluminescence (TL) measurements, we reveal the presence of a trap distribution in the host.…”

Revealing trap depth distributions in persistent phosphors

“…42 The presence of such a continuous trap distribution directly influences the shape of the TL glow peaks by broadening them, and can also explain the observed t −1 decay behavior of the afterglow, 31 although other authors suggest this behavior could be due to a trapping mechanism governed by tunneling. 43 In principle, these two explanations could be experimentally distinguished, since the t −1 behavior in the case of a continuous trap depth distribution is dependent on the temperature (at different temperatures greater or smaller parts of the distribution are filled), while tunneling is temperature independent. However, such an experimental verification is beyond the scope of this text.…”