Abstract
Electrophoresis deposition (EPD) of nanodiamond was found to be a very efficient process in forming the nucleation sites for the growth of ultrananocrystalline diamond (UNCD) films. Transmission electron microscopic investigations showed that the EPD-derived UNCD films grown on planar Si substrates contain uniform granular structure with sharp, smooth, and conductive UNCD-to-Si interface layer, which helps in better electron field emission (EFE) properties of the UNCD films. Moreover, contrary to ultrasonication process for nucleating the diamond, the EPD process is a gentle one that induced no damage to the silicon nanowire arrays (SiNWs), facilitating the formation of nuclei for growing UNCD films on SiNWs. Such a gentle process significantly enhanced the EFE properties of UNCD/SiNWs. The EPD-derived UNCD/SiNW emitters show superior EFE performances to the planar UNCD films, that is, a turn-on field of 7.19 V/μm and a large EFE current density of 2.21 mA/cm 2 at 15.0 V/μm. Furthermore, a parallel plate plasma device fabricated using the EPD-derived UNCD/SiNW nanostructures as cathode shows a high Ar plasma current value of 3.5 mA/cm 2 at a low applied field of 0.35 V/μm. These results demonstrate that these EPD-derived UNCD/SiNW nanostructures have great potential for the applications in flat panel displays due to their superior EFE properties and plasma illumination performances. © 2012 American Chemical Society.