GaN taper rods: Solid-phase synthesis, crystal defects, and optical properties

Wurtzite GaN taper rods assembled from highly oriented nanoparticles were synthesized using NaNH2 and the as-synthesized GaOOH prismatic rods as reactants at 600 degrees C for 5 h. The lengths of the GaN taper rods are in the range of 4-6 mu m and the diameters are about 0.5-1.5 mu m. It was found that a slow heating rate (1 degrees C min(-1)) was beneficial to keeping the one-dimensional (ID) skeleton of GaN, otherwise only GaN nanoparticles were obtained with a quick heating rate (10 degrees C min(-1)). Selected area electron diffraction (SAED) patterns and high-resolution transmission electron microscopy (HRTEM) observations revealed that the GaN taper rods assembled from highly oriented nanoparticles and there were crystal defects in the GaN structure. The GaN taper rods displayed luminescence emission in the blue-violet region, which may be related to crystal defects. (C) 2008 Published by Elsevier Inc.