Regensburg 2010 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 76: Nanostructures at surfaces: Wires, tubes

O 76.4: Vortrag

Donnerstag, 25. März 2010, 15:45–16:00, H38

STM induced electroluminescence from individual CdSe nanowires — •Theresa Lutz¹, Alexander Kabakchiev¹, Thomas Dufaux¹, Christian Wolpert¹, Marko Burghard¹, Klaus Kuhnke¹, and Klaus Kern^1,2 — ¹Max Planck Institute for Solid State Research, Stuttgart — ²Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland

Scanning tunneling microscopy (STM) not only provides the ultimate tool to obtain atomic scale information in both topographic and spectroscopic measurements at surfaces, but can also be employed to stimulate local photon emission. Here we show STM induced luminescence on individual semiconducting CdSe nanowires in combination with topographic and tunneling spectroscopic measurements at liquid He temperature. We investigate individual CdSe nanowires[1] with average diameters of 8 nm to 22 nm deposited onto a gold surface. The generated luminescence is ascribed to electron-hole recombination in the wire and requires hole injection from the STM-tip in excess of several hundred meV above the luminescence energy. The luminescence spectra are similar to the ones obtained in photoluminescence. Interestingly, the STM-induced luminescence is found even in the absence of tip-induced plasmonic emission, which stands in contrast to studies on similar systems in which light emission and plasmon observation seem to be coupled. We find that the energy of the emission line depends on the diameter of the wire as expected for quantum confinement of the charge carriers to one dimension.

[1] Z. Li et al., Small 4, 1698-1702 (2008)