The origin of yellow band emission and cathodoluminescence of Au-catalyzed wurtzite GaN nanowires

Abstract

GaN nanowires with large yield are directly synthesized by simply ammoniating the gallium oxide powders in the presence of ammonia gas at 1000°C, under the assistance of Au nanocatalysts. The microstructure and crystallinity of as-synthesized GaN nanowires are well studied by using high-resolution transmission electron microscope (HRTEM) and some structural defects such as stacking faults are found in the GaN nano-crystal. Cathodoluminescence measurement shows that a strong near-band-edge (NBE) emission band centered at 384nm and a broad yellow band in the range of 500–800nm are observed. Finally, the growth mechanism and possible optical emission process of GaN nanowires are discussed.