Improvement of the fabrication process for top-down GaN nanowires using contactless photo-assisted electrochemical etching

Abstract Contactless photo-assisted electrochemical (CL-PEC) etching and successive alkaline solution treatment were applied for the fabrication of GaN nanowires (NWs) using a top-down approach. By using Cr as an etching mask instead of the Ti used in the previous study, miniaturization of the size, as well as the improvement of the uniformity in shape and size, was achieved, and GaN NWs with an average diameter of 59 nm were obtained. We also attempted to increase the etching rate by installing an additional UVA light source in the etching system and achieved a shorter processing time by a factor of approximately two.