Strong luminescence from dislocation-free GaN nanopillars

GaN nanostructures were prepared on Si(111) by a hot-wall epitaxy technique employing the modified two-step growth method. Isolated hexagonal pillar-like GaN nanostructures (GaN nanopillars) with the typical diameter, height, and density of 200-300 nm, 0.5-1 mum, and 3-4x10(8) cm(-2), respectively, are self-organized without intentional pre-processing to the Si substrate. The photoluminescence and cathodoluminescence (CL) measurements show the strong near-band-edge emissions without the yellow band at room temperature. Stronger CL is obtained from the GaN nanopillars in comparison to single-crystalline GaN. The obtained strong CL is related to high crystal quality of the dislocation-free GaN nanopillars. (C) 2004 American Institute of Physics.