Role of Energy Migration in Nonradiative Relaxation Processes in ErxY2-xSiO5 Crystalline Thin Films

ErxY2-xSiO5 crystals have been proposed for compact waveguide amplifiers in Si photonics. However, the crystalline materials show quenching behavior with increasing Er concentration. We have investigated the nonradiative relaxation processes in ErxY2-xSiO5 crystallites and discussed the contribution of energy migration in ErxY2-xSiO5 crystallites. It has been found that the quenching behavior is governed by the diffusion-limited relaxation in ErxY2-xSiO5 grains, where, as we have proposed, the grain boundaries act as quenching centers. The experimental results were shown to be consistent with the diffusion-limited relaxation model. Using the proposed model, the energy transfer constant between Er ions C and the critical transfer length R0 were estimated. The values are in good agreement with the values reported previously.