Growth of Self-Organized GaN Nanostructures on Al₂O₃(0001) by RF-Radical Source Molecular Beam Epitaxy

Columnar GaN nanostructures (GaN nanocolumns) were grown on Al 2 O 3 (0001) by RF-radical source molecular beam epitaxy (RF-MBE) through a self-organization process. The nanocolumns were grown at high density, with the c -axis maintained perpendicular to the substrate surface. The dependence of column diameter and density on growth conditions was systematically investigated. The average diameter was minimized to 53 nm and the density of the GaN nanocolumns was 130×10 12 columns per square meter.