Band-edge-related luminescence due to the energy backtransfer in Yb-doped InP

Band-edge-related photoluminescence in Yb-doped InP was investigated by solving rate equations. For InP:Yb, two characteristic properties have been observed in the band-edge-related luminescence. One is that the decay curve of the band-edge-related luminescence has a slowly decaying component above about 100 K, which has not been observed in undoped InP. The other is that the luminesce intensity shows an increase at around 120 K, although that for undoped InP monotonically decreases as temperature increases. These two properties were investigated based on a proposed model of energy transfer between the Yb 4f shell and the InP–host electrical state. In the model, it is assumed that a nonradiative multiphonon transition process assists the energy transfer. We have shown, in a previous article, that the temperature dependence of the decay time and of the intensity of the Yb 4f shell luminescence can be explained by using this assumption. In this article, we calculated the band-edge-related luminescence properties under the same assumption. Good agreement was obtained between the calculated and experimental results. Thus, the experimentally observed characteristic properties in the band-edge-related luminescence are explained by the energy backtransfer from the excited Yb 4f shell to the host electronic state.