Growth mechanism of stacked-cone and smooth-surface GaN nanowires

Gallium nitride (GaN) nanowires were grown on uncoated or Ni-coated Si substrates by evaporation of Ga in NH3 Ar gas flow. A mixture of nanowires growing along [10 1- 0] and [0001] was obtained, where the former showed smooth surfaces and the latter showed the stacked-cone morphology. The yield of the two types of nanowires was found to depend on the NH3 flow. The reduction of NH3 flow led to fewer stacked-cone nanowires. The growth mechanisms of the two types of GaN nanowires are discussed. © 2005 American Institute of Physics.published_or_final_versio