Growth mechanism of α-Si3N4 submicron rods prepared from amorphous Si3N4 powders

Abstract Novel polycrystal α-Si 3 N 4 submicron rods have been successfully prepared from amorphous Si 3 N 4 powders. As-synthesized submicron rods have oblate section, with the size of 110–150 nm in height, 150–300 nm in width and 3 µm to tens of micrometers in length. Underlying growth mechanism was rationally proposed based on the results of X-ray diffraction analyses, scanning electron microscopy and transmission electron microscopy observations. It was demonstrated that the nucleation and crystal growth of α-Si 3 N 4 occurred simultaneously during the fabrication process of submicron α-Si 3 N 4 rods. The growth of α-Si 3 N 4 submicron rods follows vapor-solid-solid mechanism. The submicron rods grew from the surface of amorphous Si 3 N 4 powders in N 2 atmosphere without catalysts. The silicon monoxide vapor [(SiO)g], as a reaction intermediate, reacted with nitrogen [N 2 ] to form α-Si 3 N 4 seeds, further growing into the Si 3 N 4 nanowires. Finally, the Si and N atoms deposited on the surface of Si 3 N 4 nanowires and rearranged to form submicron rods.