Nanoscale electron field emissions from the bare, hydrogenated, and graphitelike-layer-covered tetrahedral amorphous carbon films

作者：Liu DP^*; Benstetter G; Frammel**erger W

来源：Journal of Applied Physics, 2006, 99(4): 044303.

DOI：10.1063/1.2171806

We have compared nanoscale electron field emissions from the bare, hydrogenated, and graphitelike-layer-covered tetrahedral amorphous carbon (ta-C) films. The electron field emission is investigated using a combination of atomic force microscopy (AFM)-based nanowear tests and conducting AFM, by simultaneously measuring the topography and the conductivity of the samples. The analysis of Fowler-Nordheim tunneling currents indicates the formation of filamentlike emission channels within ta-C films. The low-field emission from carbon films is primarily due to a field enhancement arising from conducting nanostructures inside the films. The implications of surface structures for electron field emission are discussed. Electrons are easily delocalized within sp(2)-bonded rings/chains at a film surface, which leads to an increase in the nanotip emission area. At identical emission currents of 60-80 pA, hydrogenated films are much more easily destroyed due to a relatively insulating surface structure. The results suggest that a very high emission site density, required for field-emission display applications, may be produced by locally modifying a film surface layer.

• 出版日期2006-2-15