Key Words:Nanowires;Chemical vapor deposition - Energy dispersive spectroscopy - High resolution transmission electron microscopy - Infrared spectroscopy - Raman scattering - Raw materials - Scanning electron microscopy - Semiconducting silicon compounds - X ray diffraction;Core-shell nanowires - Graphite reaction cell - Nanowire axes - Planar defects
Abstract:The β-SiC/SiO<inf>2</inf> core-shell nanowires have been synthesized with the presence of iron catalyst by chemical vapor reaction using a mixture of milled Si and SiO<inf>2</inf> powders and C<inf>3</inf>H<inf>6</inf> as the raw materials in a graphite reaction cell at lower temperature. The as-prepared nanomaterials are characterized by scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray diffraction, high-resolution transmission electron microscopy, and infrared spectroscopy. The results show that the nanowires consist of a 30-50 nm diameter single-crystalline β-SiC core wrapped with a uniform layer of about 10 nm thick amorphous SiO<inf>2</inf>, and their lengths are up to several tens of micrometers. The nanowire axes lie along the [1¯ 1 1] direction and possess a high density of planar defects. Some unique properties are found in the Raman scattering from β-SiC/SiO<inf>2</inf> core-shell nanowires, which are different from previous observations of SiC materials. The vapor-liquid-solid (VLS) mechanism was proposed to elucidate the growth process. © 2007 Elsevier B.V. All rights reserved.
Volume:308
Issue:2
Translation or Not:no
