Structure and surface effect of field emission from gallium nitride nanowires

Gallium nitride nanowires (GaN NWs) were synthesized by plasma-enhanced hot filament chemical vapor deposition under different ratios of nitrogen to hydrogen, which the GaN powder and nitrogen gas were used as the Ga and N sources. The characterization results indicate that the GaN NWs are grown in wurtzite crystalline structure with different length, diameters and surface adsorption. The field emission of GaN NWs was measured in the high vacuum condition of ∼10−6 Pa, which the results show that the turn-on field of GaN NWs changes from 0.86 to 2.8 V/μm depending on their structures and the current density can reach up to 830 μA/cm2 at the field of 6 V/μm. Combined the characterization results with the work function theory related to field emission, the origin of the field emission enhancement was analyzed, which associates with their surface potential and geometric structure. These results can enrich our knowledge on the field emission of GaN NWs and are highly related to the development of the next-generation of GaN nano-electronic devices.