Comparison of Structure and Electron-Field-Emission Behavior of Chemical-Vapor-Deposited Diamond and Pulsed-Laser-Deposited Diamond-Like Carbon Films

The correlation between the structure and the electron-field-emission behavior of chemical-vapor-deposited (CVD) diamond films and those of pulsed-laser-deposited (PLD) diamond-like carbon (DLC) films is investigated. The CVD films contain crystalline diamonds (sp3-bonds) separated from amorphous carbon (sp2-bonds), possessing a large electron-field-emission current density [(Je)CVD=140 µA/cm2at 21.6 V/µm], a low turn-on field [(E0)CVD=10 V/µm] and a single-value effective work function [(?e)CVD=0.082 eV]. In contrast, the pulsed-laser-deposited DLC films exhibit even better electron field emission properties [(Je)DLC=320 µA/cm2at 21.6 V/µm, (E0)DLC=8 V/µm] and a wide range of effective work functions [(?e)DLC=0.016-0.031 eV]. The superior electron-field-emission properties of DLC films, as compared with those of CVD diamonds, are ascribed to their nanostructured grains, which contain a mixture of sp3-bonds and sp2-bonds.