Morphology control of one-dimensional gallium nitride nanostructures by modulating the crystallinity of sacrificial gallium oxide templates

In this study, we demonstrated a method of controllably synthesizing one-dimensional nanostructures having a dense or a hollow structure using fibrous sacrificial templates with tunable crystallinity. The fibrous ga₂o₃ templates were prepared by calcining the polymer/gallium precursor nanofiber synthesized by an electrospinning process, and their crystallinity was varied by controlling the calcination temperature from 500^oC to 900^oC. gaN nanostructures were transformed by nitriding the ga₂o₃ nanofibers using NH₃ gas. All of the transformed gaN nanostructures maintained a one-dimensional structure well and exhibited a diameter of about 50 nm, but their morphology was clearly distinguished according to the crystallinity of the templates. When the templates having a relatively low crystallinity were used, the transformed gaN showed a hollow nanostructure, and as the crystallinity increased, gaN was converted into a denser nanostructure. This morphological difference can be explained as being caused by the difference in the diffusion rate of ga depending on the crystallinity of ga₂o₃ during the conversion from ga₂o₃ to gaN. it is expected that this technique will make possible the tubular nanostructure synthesis of nitride functional nanomaterials.