Controllable in situ growth and photoluminescence of straight and zigzag-shaped nanowires of GaN

Straight and zigzag-shaped nanowires of GaN have been grown in situ on the surface of the gallium grains and alumina ceramic substrates by heating metallic gallium grains on alumina ceramic wafers in the presence of NH3 at 1000 and 1050 °C for 0.5 h, and their controllable synthesis was achieved by changing the reaction temperature. The growth of straight and zigzag-shaped GaN nanowires is governed by a vapor–solid (V–S) process, and the evolution of straight GaN nanowires to zigzag-shaped nanowires may arise from the change of Ga/N ratio and GaN vapor concentration in the reaction system. A strong UV emission band centered at 372(362) nm and a weak blue emission peak at 460 nm were observed from the straight and zigzag-shaped GaN nanowires.