Field emission from DLC films

Field emission measurements on diamond like carbon (DLC) films with different amounts of sp3 and sp2 carbon were carried out. Depending on the amount of sp2 carbon in the film, activated and non-activated Fowler-Nordheim like emission could be observed. The emission spots were investigated using a combination of AFM and STM, by simultaneously measuring the topography and the conductivity of the samples. In the case of sp2 rich DLC films we could observe that the emission originates from highly conducting inclusions of sp2 carbon in a matrix of insulating sp3 carbon. These inclusions are already existing on the sp2 sample by the deposition process itself and are formed by the activation on the sp3 rich sample.