Substrate-Dependent Orientation and Polytype Control in SiC Nanowires Grown on 4H-SiC Substrates

SiC nanowires were grown on monocrystalline 4H-SiC wafers by chemical vapor deposition using the vapor liquid solid growth mode. The growth direction of the nanowires was dictated by the crystallographic orientation of the 4H-SiC substrates. Two distinct types of nanowires were obtained. The first type crystallized in the 3C polytype with the < 111 > nanowire axes. These nanowires grew at 20 degrees with respect to the substrate c-planes and exhibited high densities of stacking faults on those {111} planes that are parallel to the substrate c-planes. The second type featured the 4H structure albeit with a strong stacking disorder. The stacking faults in these nanowires were perpendicular to the [0001] nanowire axes. Possible growth mechanisms that led to the formation of 3C and 4H polytypes are discussed.