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VLSI Design
Volume 13 (2001), Issue 1-4, Pages 305-309
http://dx.doi.org/10.1155/2001/18514

Electronic Transport in Self-organised Molecular Nanostructured Devices

1Centre for Self Organising Molecular Systems, The University of Leeds, Leeds LS29JT, UK
2School of Electronic and Electrical Engineering, The University of Leeds, Leeds LS29JT, UK
3Department of Physics and Astronomy, The University of Leeds, Leeds LS29JT, UK

Copyright © 2001 Hindawi Publishing Corporation. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

We analyse the frequency dependent conductivity of a system which is fabricated using the combination of a quasi 2-dimensional MBE grown metal film and an ordered self-assembled overlayer of adsorbed molecules. The molecules can self-assemble to form quasi 1-dimensional conducting columns, in which electrons can be temporarily trapped. Given the short mean free path of conducting electrons, due to surface and impurity scattering, the long range transport is modelled using a diffusion scheme through a discrete lattice, whose sites are defined by the locations of the self-organised molecular columns. Local conductivities are computed using the Kubo formalism and mapped into effective transfer rates between adjacent sites of the lattice. This model includes stochastic excursions of electrons into the molecular states, as well as the quantum mechanical details of short range transport. External nano-engineered gate fields can be used to control the residence time of carriers in molecular bands. Calculations demonstrate that the in-plane conductivity is decreased at low frequency due to electron capture in the molecular columns, and that this effect becomes stronger as the length of the columns is increased.