Tuning defect-related photoluminescence of Ge nanocrystals by stress

Ge nanocrystals embedded in SiO2 and Lu2O3 thin films were fabricated using a pulsed laser deposition method. Two dimensional finite element calculations and Raman spectra clearly revealed that the Ge nanocrystals certainly experienced greater compressive stress in a Lu2O3 thin film than in a SiO2 thin film. This may lead to much more stress-relaxing defects at the interface of Ge nanocrystals embedded in a Lu2O3 thin film and thus enhances the intensity of defect-related photoluminescence. The findings presented here indicate that the matrix environment of the nanocrystals plays a significant role in the defect-related photoluminescence property