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HL: Fachverband Halbleiterphysik

HL 63: II-VI-Compounds

HL 63.2: Vortrag

Mittwoch, 16. März 2011, 16:00–16:15, POT 151

Optical properties of photonic molecules on base of the II-VI material system — •Moritz Seyfried, Kathrin Sebald, Arne Gust, Carsten Kruse, Detlef Hommel, and Jürgen Gutowski — Institute of Solid State Physics, University of Bremen, P.O. Box 330 440, D-28334 Bremen, Germany

Photonic molecules (PMs), consisting of pillar microcavities (MCs) which are connected by a small bar, offer the possibility to couple spatially separated quantum dots (QDs) in the individual pillars via the moderation of the electromagnetic field. Therefore, PMs with pillar diameters of 2.78µm and different center-to-center (CC) distances of the individual pillars were prepared out of planar monolithic VCSEL structures by using focused-ion-beam etching. The structures were grown by molecular beam epitaxy containing either one CdSe/ZnSSe QD layer or, as a more homogeneous illumination source for the far field studies, three quantum well layers as active material. Quality factors of up to 6000 could be determined from the measured discrete mode spectra of the PMs. The photoluminescence spectra were studied in dependence on the excitation position on the PM as well as on the CC distance of the individual pillars. A reduction of the spectral separation of the fundamental mode and the first higher mode with increasing CC distance was found and attributed to the reduced mode coupling for PMs with a larger CC distance. Furthermore, the electromagnetic field distribution was studied by means of the far-field pattern and is discussed with respect to the different CC distances. For a better insight the experimental data are compared with simulations.