Theory for photoluminescence from SiO2 films containing Si nanocrystals and Er ions

Abstract

In this article, the reported experimental phenomena of energy transfer from Si nanocrystals (nc-Si) to Er ions inside the SiO 2 surrounding the nc-Si or at the nc-Si/SiO 2 interface, and the origin of the characteristic double photoluminescence (PL) peaks in the SiO 2 film containing nc-Si and Er ions [Fujii et al. Appl. Phys. Lett. 71, 1198 (1997)] are explained by means of the quantum confinement–luminescence center model. The theoretical results show that the PL peak at 0.805 eV is caused by a recombination process outside the nc-Si, i.e. the electron–heavy-hole pairs tunnel into the SiO 2 barrier, are absorbed, and then recombine radiatively in the Er ions. The PL peak at 1.53 eV most probably originates mainly from another type of defects or impurities in the SiO 2 barrier or at the nc-Si/SiO 2 interface. The experimental results, that as the concentration of Er ions increases the intensity of PL peak at 0.805 eV increases while the intensity of PL peak at 1.53 eV decreases, have been explained.