Morphology control of single-crystalline Si3N4 nanomaterials

Abstract Three kinds of single-crystalline Si 3 N 4 nanomaterials, Si 3 N 4 nanowires, nanobelts and nanosheets, were synthesized by the heat treatment of Si powder in N 2 gas. The Si 3 N 4 nanowires and nanobelts are produced when the synthesis temperature and flow rate of N 2 gas are lower than 1300 °C and 0.5 l/min, respectively. The number ratio of Si 3 N 4 nanowires to Si 3 N 4 nanobelts decreases with increase in the synthesis temperature and flow rate of N 2 gas. When synthesis temperature and flow rate of N 2 gas are higher than 1400 °C and 0.75 l/min, respectively, a lot of Si 3 N 4 nanosheets of at least 2 μm in width and ranging from 1.5 to 4 nm in thickness are produced. The width of Si 3 N 4 nanomaterials increased with increase in the flow rate of N 2 gas. Thus the morphology of Si 3 N 4 nanomaterials can be controlled by changing not only synthesis temperature but also flow rate of N 2 gas.