Preparation and photoluminescence properties of Ge nanocrystals embedded in Lu2O3 matrices with a Ge-GeOx core-shell structure

Core-shell structure Ge nanocrystals embedded in Lu2O3 matrix thin films have been fabricated using the pulse laser deposition method with post-deposition annealing. X-ray diffraction pattern was analyzed by the Rietveld refinement method. The refinement result indicated the bond length of Ge core decreases in the annealed sample. After annealing in air, the GeOx oxidation layer encapsulated the Ge core, which suffered the compressive strain from the GeOx shell. This core-shell structure Ge nanocrystals would induce much more defects in the interface between the core and the shell, and thus enhanced the photoluminescence