Photoluminescence from silicon nano-particles synthesized by laser-induceddecomposition of silane

This work deals with photoluminescence study of silicon nanoparticles produ ced by CO2-laser-induced decomposition of SiH4 mixed to helium in a control led atmosphere reactor. By adjusting the pressure of both reactor and precu rsor gas and its dilution rate in helium, we were able to control, to a cer tain extent, the silicon growth rate and hence the particle diameter. This latter was determined by both small angle neutron scattering techniques and high resolution transmission electron microscopy observations. Particles w ith mean diameter ranging between 3 and 10 nm were submitted to photolumine scence and infrared absorption spectroscopy measurements. The photoluminesc ence spectra revealed two main peaks at about 1.7 and 2.1 eV. The peak posi tion of the former was insensitive to the change of particle size, while it s intensity increased after oxidation. The latter showed, however, a slight size dependence but had undergone a drastic decrease after oxidation. Thes e features enabled us to ascribe the red peak (1.7 eV) to some radiative su rface defect, while the yellow peak (2.1 eV) appeared consistent with an em ission from an oxygen-related defect such as the nonbridging oxygen hole ce nter. (C) 2000 American Institute of Physics. [S0021- 8979(00)04318-8].