Control of growth orientation of GaN nanowires

Bulk-quantity GaN nanowires of wurtzite hexagonal structure were synthesized by using hot-filament chemical vapor deposition. GaN nanowires showed two distinctive temperature-dependent growth directions. At a substrate temperature of 900–950 °C, the growth direction of GaN nanowires was perpendicular to the {1 0 1̄1} plane, while at 800–900 °C, the growth direction was perpendicular to {0 0 0 2}plane. The two directions are different from the 〈1 0 1̄0〉 direction, which is common for GaN nanowires grown to date. The difference in growth direction may be due to different growth mechanisms. In this study, the nanowires grew via a vapor–solid mechanism instead of the VLS growth mechanism.