Preparation and photoluminescence of thin films of Ge nanoparticles embedded in Al2O3 matrices

Abstract

Thin films of Ge/Al2O3 were prepared using the pulsed laser deposition method. XRD and AFM confirmed that the structure consists of Ge nanoparticles embedded in amorphous Al2O3 matrices. A blue PL from the films was found in the wavelength region of 400-550 nm with two distinct humps in the peak. The origin of the PL is attributed to localized Ge/O-related interfacial defects. Our results show evidence that the amorphous Al2O3 matrices encapsulating the Ge nanocrystals provided them with a compact and air-tight seal preventing atmospheric oxygen from diffusing into the surface of the Ge nanoparticles even when the film was annealed at a high temperature.