Temperature dependence of the crossover between the near-infrared Er and defect-related photoluminescence bands of Ge-rich Er-dopedSiO2layers

Abstract

Temperature-dependent photoluminescence of Ge-rich ${\text{SiO}}_{2}$ in the presence or absence of Er shows a crossover between defect-related (15--150 K) and Er-related (150--295 K) emission within 1525 and 1440 nm. The origin of the near-infrared defect-related bands is discussed in the light of recombination of localized excitons in luminescence centers at the Ge $\text{cluster}/{\text{SiO}}_{2}$ interface. Time-resolved photoluminescence further enables us to illustrate the observed $1.53\text{ }\ensuremath{\mu}\text{m}$ Er emission above 150 K in terms of a phonon-assisted nonradiative energy-transfer process from the luminescence centers to the ${\text{Er}}^{3+}$ ions.