Synthesis of α silicon nitride single-crystalline nanowires by nitriding cryomilled nanocrystalline silicon powder

Si3N4 nanowires (SNNWs) have been synthesized via a novel approach involving nitriding cryomilled nanocrystalline Si powder. The SNNWs formed consist of single-crystal α-Si3N4, and are 30–100 nm in diameter and ∼10 μm in length. The formation of the Si−N−Si bond during the cryomilling process, as investigated theoretically by density functional theory, promotes the subsequent synthesis of the α-Si3N4 nanowires. The mechanism for nanowire formation appears to be a vapor–solid reaction.