Size-dependent field-emission properties from triangular-shaped GaN nanostructures

Gallium nitride (GaN) nanostructures were synthesized on Si substrates by using the vapor-phase epitaxy (VPE) method. The as-synthesized GaN nanostructures with a hexagonal, single-crystalline structure possessed a triangular cross-section with nanorod and nanowire diameters ranging from about 100 to 280 nm and from about 20 to 60 nm, respectively. The field-emission (FE) properties of the GaN nanostructures were investigated in terms of their size dependence. Turn-on fields of about 4.85 V/μm and 4.10 V/μm, respectively, for the GaN nanorods and nanowires were obtained, corresponding to field-enhancement factors of about 373 and 1427. The higher aspect ratio of the GaN nanowires compared to that of the GaN nanorods caused the differences in FE properties.