Synthesis and photoluminescence of single-crystal GaN nanorods prepared by sol-gel method

A new method was applied to prepare GaN nanorods. In this method, gallium oxide (Ga2O3) gel was firstly formed by a sol-gel processing using gallium ethanol, Ga(OC2H5)3, as a new precursor. GaN nanorods were successfully synthesized after annealing of the Ga2O3 gel at 1000 deg. C for 20 min in flowing ammonia. The as-prepared nanorods were confirmed as single crystalline GaN with wurtzite structure by X-ray diffraction (XRD), selected-area electron diffraction (SAED) and high-resolution transmission electron microscopy (HRTEM). Transmission electron microscopy (TEM) displayed that the GaN nanorods were straight and smooth, with diameters ranging from 200 nm to 1.8 μm and lengths typically up to several tens of microns. When excited by 280 nm light at room temperature, the GaN nanorods had a strong ultraviolet luminescence peak located at 369 nm and a blue luminescence peak located at 462 nm, attributed to GaN band-edge emission and the existence of the defects or surface states, respectively