Statistical model of charge transport in colloidal quantum dot array

TL;DR

This paper introduces a statistical model for charge transport in colloidal quantum dot arrays that accounts for Coulomb blockade and energetic disorder, explaining power law transients and memory effects.

Contribution

It presents a novel model combining Coulomb blockade and disorder effects, explaining complex charge transport phenomena in quantum dot arrays.

Findings

Explains power law current transients.

Describes memory effects in charge transport.

Derives a fractional Ohm's law analogue.

Abstract

A new statistical model of charge transport in colloidal quantum dot arrays is proposed. It takes into account Coulomb blockade forbidding multiple occupancy of nanocrystals and influence of energetic disorder of interdot space. The model explains power law current transients and the presence of memory effect. The fractional differential analogue of the Ohm law is found phenomenologically for nanocrystal arrays. The model combines ideas that were considered as conflicting by other authors: the Scher-Montroll idea about power law distribution of waiting times in localized states for disordered semiconductors is applied with taking into account Coulomb blockade, Novikov's condition about asymptotical power law distribution of time intervals between successful current pulses in conduction channels is fulfilled, carrier injection blocking predicted by Ginger and Greenham takes place.