Multiphonon-assisted energy transfer between Yb 4f shell and InP host

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Abstract
The energy transfer mechanism between an Yb 4f shell and an InP host was investigated, assuming that a nonradiative multiphonon process assists the energy transfer. The values of the energy involved in the energy transfer were determined from the results of optical and electrical experiments. Rate equations were solved to obtain the temperature dependence of the Yb intra‐4f‐shell luminescence decay time. The calculated results and the experimentally obtained temperature dependence agree well. The calculated temperature dependence of the Yb intra‐4f‐shell luminescence intensity also agrees with the experimental measurements. These results strongly suggest that phonon absorption and emission compensate the energy mismatch in the energy transfer processes. The calculations also indicate that the thermal quenching phenomenon is mainly determined by the energy mismatch between the recombination energy of an electron and a hole and the Yb 4f‐shell energy between the excited and ground states. On the basis of the above formulation, the Yb intra‐4f‐shell luminescence intensity under hydrostatic pressure was also investigated theoretically and compared with experimental results. The 4f‐shell luminescence recovery at elevated temperature under hydrostatic pressure was qualitatively explained in the framework of the present model. The characteristic behavior of the thermal quenching in other rare‐earth doped semiconductors could also be explained qualitatively assuming that the energy transfer mechanism is similar to the one for InP:Yb.