Fabrication of GaN nanowires and nanoribbons by a catalyst assisted vapor-liquid-solid process

Wurtzite GaN nanowires and nanoribbons were produced directly from Ga metal by an Au catalyst assisted thermal evaporation process in a flowing ammonia atmosphere. We have investigated the effect of different experimental parameters on the morphology of the nanoforms. The diameters of the nanowires were varied between 20 and 40 nm while the widths of the nanoribbons were within 100-250 nm. Microstructural studies by TEM reveals the role of vapor-liquid-solid process in the nucleation of GaN nanoforms. The evolution of the ribbon like morphology was attributed to the vapor-solid process. Photoluminescence study showed UV-blue emission from the GaN nanostructures. Field emission studies indicated the possibility of these materials to be used as the cathode materials in field emission based devices.