Effect of morphology on electron emission characteristics of pulsed laser deposited diamond-like films

Electron field emission of diamond-like carbon (DLC) films synthesized by pulsed laser deposition technique at 400 degrees C substrate temperature (0.1 mbar N-2 ambient pressure) was turned on at a low electric field as E-1 = 11.6 V/mu m and a secondary deflection in current-voltage (I-V) curve occurred at E-2 = 17.4 V/mu m. The films attained a high emission current density as J = 120 mu/cm(2) under 22 V/mu m applied field. The effective work function estimated from the Fowler-Nordheim plot were phi(1)' = 0.021 eV and phi(2)' = 0.042 eV for low-turn-on regime (E-1 < E-2) and high-turn-on regime (E-2 < E), respectively. The phenomenon of double phi' with a low value in I-V characteristics was attributed to the presence of dual-morphology, i.e., the clusters and the wavy surface, which enhanced the electric field concentration with geometric factors of alpha(1) = 72 and alpha(2) = 36, respectively.