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HL: Fachverband Halbleiterphysik
HL 16: III-V semiconductors II
HL 16.6: Talk
Tuesday, March 24, 2009, 11:00–11:15, POT 151
Electrical conductivity in InN nanowires — •Florian Werner1, Friederich Limbach2, Michael Carsten1, Christian Denker1, Joerg Malindretos1, and Angela Rizzi1 — 1IV. Physikalisches Institut, Georg-August-Universität Göttingen, Germany — 2Institut für Bio- und Nanosysteme (IBN-1), Forschungszentrum Jülich GmbH, Germany
Electrical conductance through InN nanowires strongly depends on their geometry and on the carrier distribution inside them. By measuring wires of different radii and lengths in a four-point probe geometry, quadratic contributions from the bulk and linear contributions from the surface can be distinguished. The linear contribution is attributed to a high density electron accumulation layer which had previously been confirmed by Raman and photoluminescence spectroscopy. The electron accumulation layer is demonstrated to dominate the conductance through wires with less than 55 nm in diameter, although the influence of the bulk conductance cannot be neglected even for small wires. Evidence of a thin surface layer of indium oxide is provided by X-ray core level photoemission spectroscopy. Therefore the electron accumulation layer is expected to form at the InN/In2O3 interface. The surface oxide forms a tunneling barrier between the contacts and the electron accumulation layer and therefore has a strong impact on the contact resistance.