Photoluminescence from Magnetron Sputtered SiO2 Films Co-doped with (Er, Ge) under Excitation of a 325 nm He-Cd Laser Line

We have studied photoluminescence (PL) from SiO2 films co- doped with (Er, Ge) deposited by magnetron sputtering of an Er+Ge+SiO2 composite target in pure Ar ambient. Under excitation of a 325 nm He-Cd laser line, blue emission bands around 400 nm and near infrared bands around 800 nm have been observed, which are attributed to Ge-related defects and Ge nanoclusters (Ge-ncls), respectively. Strong Er3+ PL at 1.54 μm was also observed from the films, while the Er PL intensity of a control Er-doped SiO2 film (i.e., without Ge), is negligible under the same excitation. All the PL intensities vary as functions of thermal annealing temperatures. The results demonstrate that the significant enhancement of Er PL in the (Er, Ge) co-doped SiO2 films are due to the incorporation of Ge. The roles of Ge-ncls and Ge-related defects to the Er3+ excitation are discussed.