Luminescence and X-ray diffraction studies of Ge nanocrystals in amorphous silicon oxide

Ge nanocrystals embedded in a-SiO2 films have been synthesized by rapid thermal annealing. Under excitation sources of different wavelengths, three photoluminescence (PL) peaks at 1.8, 2.2 and 3.1 eV were observed. A forming gas anneal on the samples resulted in a reduction of the intensity of the PL peaks. Studies of the annealed samples by X-ray diffraction revealed the formation of GeO2 and Ge nanocrystals in the rapid thermal annealed system. The origin of the PL peaks is suggested to be due to defect related mechanism.