Self-catalytic growth of single-phase AlGaN alloy nanowires by chemical vapor deposition

Wurtzite structured AlGaN alloy nanowires over the entire compositional range have been grown on silicon (100) substrates by chemical vapor deposition using NH3 vapor and a mixture of Al powders and molten Ga droplets. The morphology, structure, and compositions were characterized by scanning and transmission electron microscopies, energy dispersive x-ray analysis, and micro-Raman scattering. The nanowires grow along the < 0001 > direction and remain as a single phase alloy, despite their small diameter. At comparable diameters, previous studies had shown that AlGaN nanowires would have spontaneously phase separated. The growth of the nanowires is suggested as via a self-catalytic vapor-liquid-solid mechanism.