A simple method to synthesize Si3N4 and Si/SiO2 nanowires from Si or Si/SiO2 mixture

Si3N4 nanowires and SiO2 amorphous nanowires with diameters of 10-70 and 10 -300 nm, respectively, have been synthesized by heating Si powders or Si/Si O2 Mixtures with or without metal catalyst at 1200 degreesC at ambient pres sure. It is found that the reactant gases (N-2 Ar and NH3) affect the yield s and morphologies of the products, and the metal catalysts are not necessa ry in growth of the Si3N4 and SiO2 nanowires. High resolution electron micr oscopy (HREM) and electron energy loss spectrum (EELS) reveal that the Si3N 4 nanowire is a single crystal covered by an amorphous SiO2 layer. The grow th mechanism is assumed to be a vapor-solid (VS) process. (C) 2001 Elsevier Science B.V. All rights reserved.