Dresden 2009 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 3: Heterostructures
HL 3.1: Vortrag
Montag, 23. März 2009, 10:15–10:30, BEY 154
Optical Modes in ZnO Nano-Pillar Resonators — •Annekatrin Hinkel, Rüdiger Schmidt-Grund, Helena Hilmer, Jesús Zúñiga Pérez, Chris Sturm, Christian Czekalla, Michael Lorenz, and Marius Grundmann — Universität Leipzig, Institut für Experimentelle Physik II, Linnéstraße 5, 04103 Leipzig, Germany
We report on cylindrical resonators, whose cavities are made of ZnO nano-wires with diameters of (50 …700) nm and length in the range of 10 µ m . The cavities, simultaneously acting as active medium, are coated with concentric cylindrical shell Bragg reflectors (BR) consisting of 10.5 pairs of YSZ and Al2O3. The ZnO nano-wires and the BRs have been fabricated by using two-step pulsed laser deposition in the high- and low-pressure regime, respectively. Both, photoluminescence and reflectivity measurements were performed on the lateral surface of the wires in dependence on the wire diameter, the temperature and the exit angle and polarization of the light. The spectroscopic features can be assigned to exciton-polariton branches in photonic wires.
Exciton-polaritons are a subject of current research. Because of its large exciton oscillator strength and binding energy, polaritons in ZnO are stable at room temperature and above. In photonic wires the photonic modes are 2D quantized, leading to modification of spontaneous emission and radiative recombination rates with respect to the 1D quantized case. Especially, lateral leakage of energy can be strongly restricted. Furthermore, the amount of polariton branches is increased. As interbranch scattering is possible, condensation of polaritons in the ground state would be enhanced.