SiC Nanowires Grown on 4H-SiC Substrates by Chemical Vapor Deposition
Growth of SiC nanowires on commercial 4H-SiC substrates by chemical vapor deposition is reported. The main objective was to explore a possibility of reproducing the substrate polytype in order to obtain SiC NWs specifically composed of the hexagonal 4H-SiC polytype. The growth experiments were conducted in a hot-wall CVD reactor with H2 as the carrier gas, SiCl4 as the silicon source, and CH3Cl as the carbon source. Vapor-liquid-solid (VLS) growth mode was enabled by using metal nano-particle on the surface of the 4H-SiC substrates. Formation of nanowires or bigger nano-cones was achieved depending on the temperature and the metal catalyst used. Only SiC phase with no presence of Si was confirmed by X-ray diffraction for the growth temperatures down to 1050°C. The low temperature photoluminescence spectra measured on as-grown NWs showed clear 4H-SiC nitrogen bound excitons in some of the samples, particularly when in-situ N2 doping was used. The density of stacking faults detected by TEM strongly depended on the growth conditions.
Anton J. Bauer, Peter Friedrichs, Michael Krieger, Gerhard Pensl, Roland Rupp and Thomas Seyller
B. Krishnan et al., "SiC Nanowires Grown on 4H-SiC Substrates by Chemical Vapor Deposition", Materials Science Forum, Vols. 645-648, pp. 187-190, 2010