Optical and electrical properties of silicon nanocrystals formed by CW laser irradiation of amorphous silicon oxides

Optical and electrical properties of silicon nanocrystals formed by CW lase r-treated hydrogenated amorphous silicon-oxygen alloys have been investigat ed as a function of the irradiation time, for different laser power densiti es and alloy compositions. Raman scattering measurements indicate that lase r irradiation yields a mixed phase structure consisting of silicon nanocrys tals (Si-nc) embedded in an oxygen-rich amorphous matrix. It is shown that both photoluminescence (PL) and electrical characteristics clearly reflect this phase separation, resulting in a wavelength-dependent PL excitation an d spectral features. Largely different conduction paths related to carrier transport within Si-nc and intergrain oxide are also detected. (C) 2001 Els evier Science B.V. All rights reserved.