Photoluminescence emitted from Si vs. Ge nanocrystals embedded in a SiO2 matrix

Luminescences from Si and Ge nanocrystals were experimentally investigated. Si and Ge ions were implanted into 300 nm-thick SiO2 films grown on crysta lline Si at an energy of 55 keV with doses of 1 x 10(17) cm(-2) and 3 x 10( 16) cm(-2) for Si implantation and at 100 keV with a dose of 3 x 10(16) cm( -2) for Ge implantation. Visible photoluminescences around 1.72 eV (720 nm) and 2.14 eV (580 cm nm) were observed from the samples annealed at 1100 de grees C after Si and Ge implantation, respectively. The results of the x-ra y photoelectron spectroscopy (XPS) measurements and passivation annealing s upported the presence of nanocrystals. The theoretical exciton energy value s in the Si and the Ge nanocrystals, based on the quantum confinement theor y, corresponded well to our experimental results.