Catalyst-free growth of In(As)P nanowires on silicon

The catalyst-free metal organic vapor phase epitaxial growth of In(As)P nanowires on silicon substrates is investigated using in situ deposited In droplets as seeds for nanowire growth. The thin substrate native oxide is found to play a crucial role in the nanowire formation. The structure of the nanowires is characterized by photoluminescence and electron microscopy measurements. The crystal structure of the InP nanowires is wurtzite with its $c$ axis perpendicular to the nanowire axis. Adding arsenic precursor to the gas phase during growth results in a bimodal photoluminescence spectrum exhibiting peak at the InAsP and InP band gap energies.