Effect of reaction temperature on formation of α-Si₃N₄ nanowires by a simple CVD method

Abstract

[Formula: see text]-Si3N4 nanowires were formed by a simple chemical vapor deposition (CVD) method using Si and SiO2 as raw materials without the addition of metal catalyst. The effect of reaction temperature on the phase composition and morphologies of the nanowires were analyzed by XRD and SEM. The experimental results indicate that a suitable reaction temperature is essential for the final products. At 1400[Formula: see text]C, small amount of target products were obtained, and some irregular particles were attached on the surfaces of nanowires. When the temperature increased to 1450[Formula: see text]C, the nanowires were mainly composed of [Formula: see text]-Si3N4 phase, they had smooth surfaces with diameters fluctuating from 50 to 200 nm and lengths from hundreds to thousands of microns. At further high reaction temperature (1500[Formula: see text]C), [Formula: see text]-Si3N4 phase was observed and the nanowires had larger diameters, this was negative for obtaining purity [Formula: see text]-Si3N4 nanowires. The growth process of [Formula: see text]-Si3N4 nanowires was dominantly governed by the vapor–solid mechanism.