Regensburg 2007 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 12: Quantum dots and wires: Optical properties I
HL 12.6: Vortrag
Montag, 26. März 2007, 16:00–16:15, H17
Colloidal Quantum Dots in High-Q Pillar Microcavities — •Verena Kohnle1, Matthias Kahl1, Tim Thomay1, Katja Beha1, Jörg Merlein1, Matthias Hagner1, Andreas Halm1, Alfred Leitenstorfer1, Rudolf Bratschitsch1, Jan Ziegler2, Thomas Nann2, Yuri Fedutik3, Mikhail Artemyev3, Ulrike Woggon3, and Fabian Pérez-Willard4 — 1Fachbereich für Physik, Centrum für angewandte Photonik, Universität Konstanz, Konstanz, Germany — 2School of Chemical Sciences and Pharmacy, University of East Anglia, Norwich, UK — 3Experimentelle Physik IIb, Universität Dortmund, Dortmund, Germany — 4DFG Center for Functional Nanostructures, Universität Karlsruhe, Karlsruhe, Germany
We have fabricated high-Q pillar resonators with colloidal CdSe/ZnS quantum dots or rods as light emitters by focused ion beam (FIB) milling. First, a planar dielectric cavity is formed by two Bragg mirrors, each consisting of sputtered pairs of alternating TiO2 and SiO2 layers. Subsequently, micropillar waveguides with diameters in the range from 5100 nm down to 610 nm are cut out of the planar resonator via FIB. Photoluminescence measurements of quantum dots in the resonator show a blue shift of the fundamental cavity mode with decreasing pillar diameter. This result demonstrates the presence of three-dimensional light confinement. The spectral position of the observed cavity modes may be calculated by modeling the pillar resonator as a waveguide with an effective refractive index. The theoretical results are in excellent agreement with the experimentally observed pillar mode patterns and frequencies.