Berlin 2012 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 95: Quantum Dots and Wires: Optical Properties III (mainly Cavities and Ultrafast Response)
HL 95.2: Vortrag
Freitag, 30. März 2012, 09:45–10:00, EW 201
Single Quantum Dot Photocurrent Spectroscopy in high-Q Micropillar Cavities — •Manuel Gschrey1, Peter Gold1, Andreas Löffler1, Sven Höfling1, Alfred Forchel1, Martin Kamp1, and Stephan Reitzenstein1,2 — 1Universität Würzburg, Technische Physik, Am Hubland, 97074 Würzburg — 2Present address: Technische Universität Berlin, Institut für Festkörperphysik, Hardenbergstraße 36, 10623 Berlin, Germany
We report on single quantum dot controlled photocurrent (PC) measurements in electrically contacted high-Q micropillar cavities in the cavity quantum electrodynamics (cQED) regime. The micropillars consist of single layer of InGaAs QD in a one λ cavity that is sandwiched between two distributed Bragg reflectors (DBR). The devices are contacted via a ring-shaped gold contact on the upper facet of the pillar. This enables the control of the emission properties of the coupled QD-cavity system via the quantum confined Stark effect. As such, PC-spectroscopy opens up the possibility of investigating and controlling the transmission properties of the coupled QD-microcavity system on a single QD level. To address the influence of cQED effects on the PC, the structure is probed under non-resonant as well as strictly resonant conditions using either sidewall excitation or excitation through the top facet of the micropillar. Single QD effects are identified via high-resolution PC spectroscopy under variation of temperature, bias voltage and excitation power. We observe pronounced changes of the photocurrent response when single QD emission lines are tuned in and of resonance with the fundamental cavity mode of a micropillar cavity.