Photoluminescence from nanometer Ge particle embedded Si oxide films

Nanometer Ge particle (NGP) embedded Si oxide films were deposited on p-type Si substrates using the rf magnetron sputtering technique with a Ge-SiO2 composite target. The area ratio percentage of the Ge target to the composite target was 5%. These films were annealed in a N-2 ambient at 300, 600, 800, or 900 degrees C for 30 min. By fitting Raman scattering spectra, the average diameters of,the NGPs in the films were determined. They increased from 5.4 to 9.5 nm with increasing annealing temperatures from 600 to 900 degrees C. The photoluminescence (PL) peaks for all NGP embedded Si oxide films annealed at various temperatures are located at almost the same position around 580 nm (2.1. eV), although the average sizes of the NGPs in these films are very different from each other. After gamma-ray irradiation, the PL peak intensity increases by a factor of 2.3, with the peak position unchanged. The PL peak position does not show any evident shift when the measurement temperature increases from 10 to 300 K. All experimental facts indicate that Light emission originates mainly from the luminescence centers in the SiOx films covering the NGPs rather than from the NGPs. The role of NGPs in the PL process of the films is discussed. (C) 1998 American Institute of Physics.