Growth mechanism of SiN nanowires from amorphous SiN powders synthesized by low-temperature vapor-phase reaction

• Published in: CrystEngComm 2016-05, Vol.18 (18), p.3247-3255
• Main Authors: Chung, Yong-Kwon, Koo, Jae-Hong, Kim, Shin-A, Chi, Eun-Ok, Cho, Jun-Young, Sohn, Woon-Bae, Kim, Mi-Young, Park, Chan
• Format: Article
• ISSN: 1466-8033
• DOI: 10.1039/c6ce00232c

A novel synthesis method to prepare Si 3 N 4 nanowires from amorphous silicon nitride (a-Si 3 N 4 ) powder synthesized by a low-temperature vapor-phase reaction method was investigated. Highly crystalline α-Si 3 N 4 nanowires were synthesized by heat treatment of the a-Si 3 N 4 powder under ammonia atmosphere. The surface of the nanowires was smooth and clean without any attached particles. The thickness of the nanowires was in the range of ∼200-300 nm with lengths of tens of micrometers. The nucleation of nanowires from the reaction between SiO and N 2 occurs on the surface of the a-Si 3 N 4 powder, which is covered by a thin layer of SiO 2 , and the nanowires grow from the rearrangement of Si and N atoms of the a-Si 3 N 4 powder. The reduction of SiO 2 to SiO by ammonia was promoted in the presence of a Ni catalyst; therefore, the growth was observed at a lower temperature when Ni was added to the a-Si 3 N 4 powder than in the presence of added Fe. The growth of α-Si 3 N 4 nanowires occurs along the [100, 101] direction and follows the vapor-solid-solid mechanism. Growth of Si 3 N 4 nanowires from amorphous Si 3 N 4 powders synthesized by low-temperature vapor-phase reaction follows the VSS mechanism.