The effect of the surface layer of tetrahedral amorphous carbon films on their tribological and electron emission properties investigated by atomic force microscopy

The nanowear resistance, tribological, and field emission properties of tetrahedral amorphous carbon (ta-C) films have been analyzed by atomic force microscope (AFM)-based wear testing technique, lateral force microscope, and conducting AFM. The ta-C films grown by filtered pulsed cathodic arc discharge were found to have soft surface layers, 1.1±0.1 nm thick, which contribute to an improvement of their field emission properties. The low friction coefficient between the nanotip and film surface is correlated to one or two graphite-like atomic layers at the ta-C film surfaces. The analysis of Fowler–Nordheim tunneling currents indicates the formation of filament-like emission channels in amorphous carbon films.