Abstract
The stacked-cone morphology GaN nanorods with diameters of 100-400 nm and lengths of tens of micrometers were synthesized by metal-catalyzed chemical vapor deposition. The stacked-cone GaN nanorods possessed dominated hexagonal crystalline structure with growth direction along [0001]. TEM analysis showed that the top tip had a bicrystal structure of hexagonal and cubic phases, while the stem and side tip had single hexagonal phase. Room temperature field emission test showed the turn-on field was 8.9 V/mu m at 0.1 mu A/cm(2) and current density was about 0.1 mA/cm(2) at 14.2 V/mu m at a vacuum gap of 70 mu m. The field enhancement factor beta and anode-cathode gap d follows a universal equation. The simple synthesis method and good emission properties imply their potential application in vacuum microelectronic.