Synthesis and Optical Properties of Single-Crystalline Silicon Nitride Nanowires with Controlled Dimensionality

Abstract

Single-crystalline silicon nitride nanowires with high purity, controlled dimensionality have been prepared via nitriding the nanocrystalline silicon powders at 1300°C~1400°C. The nanocrystalline silicon powders with average particle size of 20-80nm were obtained by cryomilling with the liquid nitrogen as the medium. Scanning electron microscopy, high resolution transmitted electron microscope, X-ray diffraction and UV-lamp microzone Raman spectrometer were used to characterize the as-synthesized nanowires. The effects of nitridation process (reaction temperature and holding time) and the particle size of nanocrystalline silicon powders on the phase and microstructure of the silicon nitride nanowires were analyzed. The obtained results show that the diameter of the nanowires can be controlled in the range of 40~100nm, and the length of 10~80 μm. The formation of the nanowires can be explained by the vapor-solid growth mechanism. The room temperature photoluminescence spectra show that the silicon nitride nanowires exhibit a broad visible emission band which ranges from 370 nm to 700 nm.