Catalyst-free growth of high-optical quality GaN nanowires by metal-organic vapor phase epitaxy

Catalyst-free GaN wires with 100-200 nm diameters are grown on bare c-sapphire substrates by a metal-organic vapor phase epitaxy approach using both low V/III ratio and V-III precursor flows that favor a reaction-limited growth regime. The polarity control of the initial seeds allows obtaining pencil-shape wires with very sharp pyramids at their top (similar to 5 nm diameter). These defect-free nanowires evidence excellent structural and optical properties as shown by a sharp photoluminescence linewidth (1-3meV at 5K). (C) 2011 American Institute of Physics. [doi: 10.1063/1.3671365]