Modulation Effects of Hydrogen on Structure and Photoluminescence of GaN Nanowires Prepared by Plasma-Enhanced Chemical Vapor Deposition

Gallium nitride (GaN) nanowires (NWs) were grown on Si(100) substrates at different hydrogen gas flow rates, using plasma-enhanced chemical vapor deposition. The size and morphology of the GaN NWs could be modulated by controlling the hydrogen atmosphere. The diameters of the GaN NWs ranged from 53 to 221 nm, and their morphology transformed from a hexagonal prism to a triangular pyramid upon changing the hydrogen atmosphere conditions. The modulation effects originated from the competitive equilibrium between surface and interfacial diffusion induced by hydrogen in the vapor–liquid–solid growth mechanism. The photoluminescence spectra of the different GaN NWs may have originated from two metabolic peaks, which were closely related to their nanostructures. These findings provide a simple and convenient method to modulate the structure of GaN NWs and may further the application of GaN in nano-optoelectronic devices.