Possible mechanisms of conductivity in the combined AFM / STM and growing quantum dots of colloidal gold

Abstract

We have obtained tunneling current - voltage characteristics for growing quantum dots of colloidal gold in the combined atomic - force and scanning tunneling microscope. It is assumed that the main contribution to current gives the ionic conductivity. A qualitative comparison of the tunneling current - voltage characteristics with the theoretical curve for field dependence of the probability of 2D - dissipative tunneling with the influence of two local phonon modes in wide - band matrix has been fulfilled. A qualitative agreement of the experimental and theoretical curves, suggesting a possible contribution of the dissipative tunneling in the tunnel current through a growing quantum dot under the needle of the cantilever, which can be amplified in clusters ranging in size from 1 to 5 nm in thinner films, has been also established.