Large scale tapered GaN rods grown by chemical vapour deposition

Large quantities of gallium nitride-tapered rods with sharp-tip were synthesized by a chemical vapour deposition method using the reaction of ammonia with the mixture of gallium oxide and carbon. The as-prepared rods have triangle cross section with lateral slope tapered to their ends; they are single-crystalline wurtzite structure crystals grown with the [112¯0] direction. The axial self-catalytic vapour–liquid–solid (VLS) growth and radial vapour–solid (VS) growth mechanism as well as the change of reactive atomic ratio (Ga/N) during growth process were believed to contribute to the formation of tapered rods.