Modelling of the electron field emission process in polycrystalline diamond-like carbon thin films

Diamond-like carbon (DLC) films are being researched as a possible cold cathode material to be used in large area flat panel displays. There are many models that attempt to account for the electron field emission process observed in these films. The initial models that were based to the fact that the emission was due purely to a negative electron affinity have now been modified. The emission from the DLC films, although following a Fowler-Nordheim type curve, do not give realistic values for the emission areas or barriers. Therefore, a model based on space charge band bending at the back junction was proposed to account for the electron emission at low electric fields from amorphous carbon (a-C). In this 'space charge interlayer' model the real cathode is the substrate, from which hot electrons are created due to the fully depleted diamond-like carbon film the electrons encounter before reaching the front surface of the film. The model based on this mechanism has already been published for nitrogenated amorphous carbon thin films. Here we extend the model to incorporate the emission of electrons from polycrystalline diamond thin films.