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 (sp(3)-bonds) separated from amorphous carbon (sp(2)-bonds), possessing a large electron-field-emission current density [(J(e))(CVD) = 140 mu A/cm(2) at 21.6 V/mu m], a low turn-on field [(E-0)(CVD) = 10 V/mu m] and a single-value effective work function [(Phi(e))(CVD) = 0.082 eV]. In contrast, the pulsed-laser-deposited DLC films exhibit even better electron field emission properties [(J(e))(DLC) = 320 mu A/cm(2) at 21.6 V/mu m, (E-0)(DLC) = 8 V/mu m] and a wide range of effective work functions [(Phi(e))(DLC) = 0.016-0.031eV]. 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 sp(3)-bonds and sp(2)-bonds.