Berlin 2008 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 3: Quantum dots: Microcavities and photonic crystals

HL 3.1: Talk

Monday, February 25, 2008, 11:15–11:30, ER 270

Optical properties of ZnSe-based quantum dot pillar microcavities at elevated temperatures — •Joachim Kalden, Henning Lohmeyer, Kathrin Sebald, Thomas Meeser, Jürgen Gutowski, Carsten Kruse, Arne Gust, and Detlef Hommel — Institute of Solid State Physics, University of Bremen, P.O. Box 330 440, D-28334 Bremen, Germany

II-IV quantum dots (QDs) are of high interest for emission in the green spectral region. CdSe QDs are embedded in monolithic ZnSe-based VCSEL structures grown by molecular beam epitaxy. In these structures the CdSe QDs are embedded inbetween MgS barriers which enhance the high temperature stability up to room temperature [1]. Pillar microcavities (MCs) with diameters down to 715 nm are prepared by focused-ion-beam (FIB) etching and optically characterized by micro-photoluminescence (µ-PL) measurements. Due to the three-dimensional optical confinement discrete mode spectra are detected and studied with regard to polarization and temperature, respectively. Experimental findings correspond to theoretical calculations [2]. Quality factors beyond 3000 are deduced from the spectral width of the fundamental MC mode (FM). Furthermore, the coupling between the single-QD emission and the FM is discussed. In this context we demonstrate how to tune the QD emission into resonance with the FM via temperature adjustment or post fabrication FIB etching. Thus, 5-fold PL intensity enhancement is achieved for individual QDs.
R. Arians et al., Appl. Phys. Lett. 90, 101114 (2007)
H. Lohmeyer et al., Appl. Phys. Lett. 88, 051101 (2006)