LIGHT-EMISSION FROM THERMALLY OXIDIZED SILICON NANOPARTICLES

Light emission characteristics from silicon nanoparticles consisting o f a crystalline core encased in an amorphous oxide shell are presented . The particles were thermally oxidized in the open atmosphere at 800 degrees C for times from 5 to 160 min in order to decrease the Si core dimensions. Photoluminescence spectra, at low excitation levels, reve al that the light emission shifts to shorter wavelengths as the oxidat ion time is increased. At high excitation levels, photoluminescence sp ectra show little or no shift. These results indicate that there are a t least two mechanisms involved with light emission from Si nanopartic les, one associated with quantum size effects and another which is ind ependent of size distribution. (C) 1994 American Institute of Physics.