AlGaN Nanocolumns and AlGaN/GaN/AlGaN Nanostructures Grown by Molecular Beam Epitaxy

This work reports on the characterization of hexagonal, single crystal AlGaN nanocolumns with diameters in the range of 30 to 100 nm grown by molecular beam epitaxy on Si(111) substrates. The change of the flux ratio between the Al and the total III-element controls the alloy composition. The Al composition trend versus the Al flux is consistent both with the E2 phonon energy values measured by inelastic light scattering and the luminescence emission peaks position. High quality low dimensional AlGaN/GaN/AlGaN heterostructures with five GaN quantum discs, 2 and 4 nm thick, embedded into the AlGaN columns, were designed in order to study the quantum confinement effects.