Growth of platelike and branched single-crystalline Si₃N ₄ whiskers

In this communication, we report for the first time the growth of platelike and branched Si₃N₄ whiskers via catalyst-assisted pyrolysis of polymeric precursors. The as-prepared whiskers are single crystalline with a uniform thickness and width. The thickness and width of the Si₃N₄ whiskers range from 200 to 300 nm and 800 to 1200 nm, respectively. The platelike α-Si₃N₄ whiskers grew along [010] direction, while the branches grew along [001] direction. A growth mechanism based on solid-liquid-gas-solid reaction/crystallization is proposed. The formation of platelike whiskers instead of cylindrical whiskers is attributed to an anisotropic growth at an early nucleation/growth stage.