AVS 45th International Symposium
    Nanometer-scale Science and Technology Division Tuesday Sessions
       Session NS-TuM

Paper NS-TuM5
Self-Assembled Single Electron Tunneling Devices

Tuesday, November 3, 1998, 9:40 am, Room 321/322/323

Session: Quantum Structures and Molecular Electronics
Presenter: L.K. Hedberg, Chalmers Univ. of Technology and Univ. of Gothenborg, Sweden
Authors: S.H.M. Persson, Chalmers Univ. of Technology and Univ. of Gothenborg, Sweden
L.K. Hedberg, Chalmers Univ. of Technology and Univ. of Gothenborg, Sweden
L.G.M. Olofsson, Chalmers Univ. of Technology and Univ. of Gothenborg, Sweden
B. Kasemo, Chalmers Univ. of Technology and Univ. of Gothenborg, Sweden
Correspondent: Click to Email
Single electron tunneling effects were studied in self-assembled devices, by contacting a nanoscale gold cluster to two gold electrodes. The size of the gold cluster was around 5 nm, which is controlled by the chemical synthesis. Coulomb blockade of tunnelling was observed at room temperature and Coulomb staircase at 4.2 K. With a third gate terminal it was possible to modulate the tunneling characteristic by electric field effect at 4.2 K. Nanoscale electronic devices can be made with refined lithographical techniques, e.g. using scanning probe instruments, but these methods are very slow and not practical for large scale fabrication. The electrodes were made by electron beam lithography and angled evaporation to control the gap between the electrodes to distances smaller than 10 nm. The surface of the gold electrodes were modified by a self-assembled monolayer of 1,8-octanedithiol and gold clusters were found to be captured in the electrode gap after immersion of the sample in a hexane solution of clusters. The characteristic feature of single electron tunneling can be seen in the current voltage characteristic as a number of steps, that is named the Coulomb staircase. The Coulomb blockade is observed at room temperature with a blockade voltage of the order 0.2 V. Recent theoretical results@footnote 1@ predict a new "electron shuttle" mechanism for systems similar to ours, where the middle electrode is softly coupled to the outer ones via organic molecules. The softness of the molecular links implies that charge transfer could give rise to deformation of these structures. Under certain conditions this would result in oscillation of the gold nanoparticle and a current through the structure that is proportional to the cluster vibration frequency. One aim of our work is to verify these predictions experimentally. @FootnoteText@ @footnote 1@L.Y.Gorelik, A.Isacsson, M.V.Voinova, B.Kasemo, R.I.Shekter and M.Jonson, Phys. Rev. Lett., 80 (1998), 4526