Straight and helical InGaN core–shell nanowires with a high In core content

In 1− x Ga x N nanowires were fabricated in a tube furnace by chemical vapour deposition, with Ga, In and NH 3 as the starting materials and Au as the catalyst. Scanning electron microscopy showed that a mixture of straight and helical In 1− x Ga x N nanowires was obtained. Transmission electron microscopy (TEM) revealed that both types of nanowire exhibited core–shell structures. The crystal structure of the samples was studied by high resolution TEM and x-ray diffraction, and both cubic and hexagonal phases were found. Energy dispersive x-ray spectroscopy showed that the core had a high In content and the shell had a low In content. The nanowires were also characterized by photoluminescence. The mechanism of formation for the helical nanowires and core–shell structure is discussed.