Characteristics of GaN–core/Au-shell hetere-nanowires: Effects of thermal annealing on the structural and photoluminescence properties

GaN-core/Au-shell nanowires were fabricated and the effects of thermal annealing on the structural and photoluminescence (PL) properties were investigated. The surfaces of hetero-nanowires became rough due to the thermal annealing which could be attributed to the agglomeration of Au-shell layers into the cluster-like structures. X-ray diffraction indicated that the thermal annealing enhanced the crystallinity of the Au shell. From Gaussian deconvolution studies, we observed that the Au coating added a green band to the PL spectrum, whereas the thermal annealing enhanced the ultraviolet band. We have discussed the possible emission mechanisms.