Preventing optical deactivation of nanocluster Si sensitized Er using nanometer-thin SiNX/SiO2:Er heterolayer thin film

Abstract

Multilayer thin films consisting of nanometer-thin, Er-doped luminescent layers (either SiO2:Er or Si3N4:Er) interlaced with nanometer-thin, Si-rich sensitizing layers (either Si-rich oxide or Si-rich nitride) are proposed as a solution to loss of Er3+ optical activity during nanocluster Si (nc-Si) sensitization of Er3+. Comparison of Er3+ photoluminescence (PL) intensities and luminescence lifetimes under both direct, resonant pumping and under nc-Si sensitized pumping shows that by using a heterolayer structure that consists of Si-rich silicon nitride sensitization layers with SiO2:Er luminescing layers, anneal-induced optical deactivation and desensitization of Er3+ that often accompany nc-Si sensitization can be prevented such that the most effective nc-Si sensitization and strongest Er3+ activity can be obtained simultaneously without a compromise between the two. Based on high-resolution transmission electron microscopy and PL spectroscopy, we identify the maintenance of compositional and structural integrity of the heterolayer thin film through the use of nitride layers, and the subsequent maintenance of subnanometer scale spatial separation between nc-Si and Er3+ even after high temperature annealing at 1050 degrees C as being the critical factors for the observed advantage of the heterostructure. (C) 2010 American Institute of Physics. [doi:10.1063/1.3489972]