Direction-dependent homoepitaxial growth of GaN nanowires

GaN nanowires with vastly different morphologies depending upon the growth direction are produced by direct nitridation and vapor transport of Gain disassociated ammonia. Nanowires grown homoepitaxially along the c-direction develop hexagonal-prism island morphologies (see Figure, left, and Cover), while wires grown along the a-direction form uniform, belt-shaped morphologies (Figure, right). A ballistic transport phenomenon for adatoms is proposed to explain the observed prismatic island morphologies.