Synthesis and field emission properties of hybrid structures of ultrananocrystalline diamond and vertically aligned carbon nanofibers

Ultrananocrystalline diamond (UNCD) films with and without nitrogen doping were deposited onto vertically aligned carbon nanofibers (VACNFs). The field emission properties of these hybrid structures were studied. It is found that the UNCD films were deposited on VACNFs with a high degree of conformality using an optimized seeding process. This hybrid structures exhibited greatly improved macroscopic field emission performance compared with uncoated VACNFs. Further enhancement was observed for nitrogen-doped UNCD on VACNFs, with low threshold field emission (2.5 V/μm) and low work functions for the field emission. The stability of the emission was also improved as compared to the uncoated VACNFs.