Published online by Cambridge University Press: 21 February 2011
We report on the growth and characterization of three dimensional nanoscale structures of GaN. GaN dots were grown by metal organic chemical vapor deposition (MOCVD) on 6H-SiC substrates. The actual size of the dots measured by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) ranged from ∼20 nm to more than 2 μm. The average dot density ranged from 107 to 109 cm−2. The single crystal structure of the dots was verified by reflectance high energy electron diffraction (HEED) and TEM. Cathodoluminescence (CL) and photoluminescence (PL) of the dots were studied at various temperatures and excitation levels. The PL and CL edge peak for the GaN dots exhibited a blue shift as compared with edge peak position for continuous GaN layers grown on SiC.