Catalyst-free and controllable growth of SiCxNy nanorods

Non vapor-liquid-solid (VLS) method of growing high-purity silicon carbon n itride (SiCxNy) nanorods with rod widths ranging from 10 to 60 nm and lengt hs of microns is reported. Unlike the case for the ordinary VLS or catalyst -mediated growth, the two-stage process presented here is a catalyst-free a pproach since it does not involve any catalyst during the growth of the nan orods. The first stage involves formation of a buffer layer containing vari ous densities of SiCxNy nanocrystals by electron cyclotron resonance plasma enhanced chemical vapor deposition (PECVD); whereas the second stage invol ves a high growth rate along a preferred orientation to produce high-aspect -ratio nanorods using microwave PECVD. Moreover, the number density and the diameter of the nanorods can be controlled by the number density and the s ize of the nanocrystals in the buffer layer. Production of quasi-aligned Si CxNy, nanorods with a number density of the rods as high as 10(10) cm(-2) h as been achieved. The SiCxNy nanorods thus produced exhibit good field emis sion characteristics with stable operation over 8 It. The approach presente d here provides a new advance to synthesize nanorod materials in a controll able manner. (C) 2001 Elsevier Science Ltd. All rights reserved.