EVALUATION OF THE ENERGY-TRANSFER RATE BETWEEN AN ER 4F SHELL AND A SI HOST IN ER-DOPED SI

We estimated the energy-transfer rate between an erbium (Er) 4f shell and a Si host by using two independent measurements. The first method involved measuring the temperature dependence of the decay time of Er 4f-shell luminescence and obtaining the energy-transfer rate by assumi ng that the energy transfer is assisted by nonradiative multiphonon pr ocesses and that thermal quenching is due to an energy back-transfer m echanism. The estimated value was 2 x 10(8) s(-1). The second method i nvolved measuring the time response for luminescence intensity after p ulsed host photoexcitation. Although some tens of mu s luminescence de lay after host excitation has been reported, we found that the slow re sponse time of the detection system may cause spurious delay. We measu red the luminescence decay curve using a system with a fast response t ime and analyzed the data, taking into account the system response tim e. The energy transfer rate was estimated to be at least 10(7) s(-1). This estimation is consistent with the result obtained by the first me thod, mentioned above, confirming a rather large energy-transfer rate between the Er 4f shell and Si host. (C) 1998 American Institute of Ph ysics. [S0021-8979(98)04120-6].