Optical gain in monodispersed silicon nanocrystals

Stimulated emission from silicon-nanocrystal planar waveguides grown via phase separation and thermal crystallization of SiO/SiO2 superlattices is presented. Under high power pulsed excitation, positive optical gain can be observed once a good optical confinement in the waveguide is achieved and the silicon nanocrystals have proper size. A critical tradeoff between Auger nonradiative recombination processes and stimulated emission is observed. The measured large gain values are explained by the small size dispersion in these silicon nanocrystals. (C) 2004 American Institute of Physics.