ИСТИНА

Correlations between field emission (FE) properties and surface structure of few-layer graphene (FLG) flakes have been examined. Films consisting of the flakes oriented perpendicularly to the flat Si substrates were obtained by a PECVD method. FLG flakes had thickness of 5-10 nm and width and height of 1-3 um. The FE characteristics of the FLG films were studied depending on the various surface-sensitive effects: adsorption of residual gases, ion bombardment and thermal oxidation. It was found that thermal oxidation in air at temperatures up to 800 C produces a big amount of 100 nm sized through-hole defects in the lateral side of the flakes. Nevertheless the FE properties of the oxidized films remained almost the same as for as-grown material. At the same time electron emission in the harsh ion bombardment conditions led to the strong degradation of the FE properties. However it was revealed no considerable changes in the form and size of the flakes. Using the structural analysis of FLG performed by TEM, SEM and Raman techniques, the possible mechanisms responsible for the observed FE changes are discussed.