Effect of substrate orientation on the catalyst-free growth of InP nanowires

We report the fabrication of self-catalysed InP nanowires on (111)B, (111)A, (110), and (001) InP substrates. Indium droplets, deposited in situ using metalorganic vapour phase epitaxy, are used as seeds for nanowire growth. The preferential nanowire growth direction is always ⟨111⟩ B on (111)B, (111)A, and (110) oriented substrates. On (111)A substrates some initial growth in the [111]A direction is observed before kinking into one of the available ⟨111⟩B directions. The nanowires are optically active at room temperature. On (001) substrates no nanowire growth off the substrate is observed. However, growth still takes place in the two possible equivalent ⟨111⟩B azimuthal directions.