Morphology and growth mechanism of gallium nitride nanotowers synthesized by metal–organic chemical vapor deposition

Two kinds of novel GaN nanotowers on silicon (1 1 1) substrates by employing ultrathin Ni catalyst films (0.2 nm) were successfully synthesized at different growth temperatures using a metal–organic chemical vapor deposition system. Scanning electron microscopy indicated that the density and growth direction of the nanotowers were highly sensitive to changes of growth temperature. The morphologies were characterized in detail, and showed triangular and hexagonal nanotowers which were oriented predominantly along [112¯0] and [0 0 0 1] directions, respectively. Finally, a new growth mechanism is stated to explain the growth of these two novel GaN nanotowers.

► Two kinds of novel GaN nanotowers were synthesized by MOCVD.
► Triangular nanotowers were oriented along [1 1 2¯ 0] direction.
► Hexagonal nanotowers were oriented along [0 0 0 1] direction.