Study on the chemical synthesis process of Ga2O3 nanowires and their ultraviolet light sensor properties

We investigated the chemical synthesis process of Ga2O3 nanowires including the effect of HCl addition, the post-growth crystallization properties after heat treatment, and their ultraviolet (UV) light sensor properties. Changes in the shape and crystal structure were confirmed at each step of the nanowire synthesis. We found that the addition of HCl to the raw materials reduced the nanowire diameter and increased the bandgap energy. We also found that, during post-growth crystallization by heat treatment, the phase transition temperature of nanowires from epsilon-type to beta-type was about 300 degrees C lower than the temperatures known for bulk and thin films, even when HCl was mixed during synthesis. The responsivity of UV sensors using the nanowire networks was much better than the previously reported values of similar Ga2O3 nanowire devices, probably due to the large surface area to volume ratio.