Arrays of p-type silicon micro-emitters have been formed using a subtractive tip fabrication technique. Following fabrication, the emitter surface was coated with GaN nanoparticles and nanocrystalline diamond by a dielectrophoresis deposition technique. The emitters were evaluated and compared before and after the surface treatment using I-V measurements in the diode configuration. The phosphor screen, used as the anode, was spaced nominally about 70 µm from the cathode. The field emission characteristics were measured in a high vacuum chamber at a pressure range between 10−5and 10−8Torr. The results suggest that the emitters benefit from coating the surface with nanocrystalline diamond in terms of reduction in the turn on voltage, GaN coating increase the turn on voltage. Both diamond and GaN improved the emission uniformity in the region of the low voltage operation.