Geometrical field enhancement on micropatterned nanodiamond film for electron emissions

We report a technique to uniformly micropattern nanodiamond films using reactive ion etch (RIE) process and thereby study the effect of the geometrical field enhancement for electron emissions in vacuum. Nanodiamond films with grain size as small as 5–10 nm were deposited by employing a growth-rate control technique with a process of CH4/H2/N2 microwave plasma enhanced chemical vapor deposition (MPECVD). The nanodiamond film was micropatterned to yield lateral 6-finger, 4-finger, and edge emitters using a single-mask process employing the RIE. The as-deposited nanodiamond film, the 6-fingered emitter, and the edge-shaped lateral emitter were tested for vacuum field emission and their characteristics compared. The effect of the geometrical field enhancement offered by the micropatterned finger-like emitter structures over the edge emitters and the as-deposited nanodiamond film was established experimentally. SIMION 7.0™ simulation software was subsequently used to model the lateral emitter geometries and study their equipotentials and electric field distributions to corroborate the geometrical field enhancement offered by the fingered emitters.