ИСТИНА

heoretical consideration of field electron emission from nanostructures weakly coupled to the cathode shows that, under certain conditions, charge transport in such a system can be governed by the Coulomb blockade effect, which leads to a stepwise increase of the emission current with an applied voltage (Coulomb staircase) due to single-electron charging of the nanostructure [1]. Several experimental observations of Coulomb staircase in field emission current-voltage characteristics of various nanostructures [2–4] have been reported over the last decade. Recently, in experiments with heterostructured carbon nanotips, we observed an additional short-period modulation of the field emission current amplitude in the Coulomb staircase, which was explained by the presence of discrete energy states arising due to the quantum confinement in the emitting nanostructure [5]. In this report, we present a numerical simulation of such heterostructured field emitters that takes into account the combined effect of single-electron charging and quantum confinement. The model of the system is based on the theory of Coulomb blockade in quantum dots [6] in combination with the theory of field emission. We calculated the current-voltage curves for various parameters of the emitting structure at different temperatures of the system. As a result of simulations, the values of the model parameters corresponding to various regimes of charge transport were determined. The results obtained can be used in the studies of heterostructured systems, consisting of quantum dots attached to nanotips, which are widely explored at present.