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

Abstract

In1−xGaxN nanowires were fabricated in a tube furnace by chemical vapour deposition, with Ga, In andNH3 as the starting materials and Au as the catalyst. Scanningelectron microscopy showed that a mixture of straight and helicalIn1−xGaxN nanowires was obtained. Transmission electron microscopy (TEM) revealed that both typesof nanowire exhibited core–shell structures. The crystal structure of the samples wasstudied by high resolution TEM and x-ray diffraction, and both cubic and hexagonalphases were found. Energy dispersive x-ray spectroscopy showed that the core had a highIn content and the shell had a low In content. The nanowires were also characterized byphotoluminescence. The mechanism of formation for the helical nanowires and core–shellstructure is discussed.