Regensburg 2010 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 24: Quantum Dots and Wires, Optical Properties II: Single Photon Sources

HL 24.1: Talk

Tuesday, March 23, 2010, 11:30–11:45, H17

Electrically driven quantum dot-micropillar single photon source with 34% overall efficiency — •Tobias Heindel, Christian Schneider, Matthias Lermer, Soon-Hong Kwon, Tristan Braun, Stephan Reitzenstein, Sven Höfling, Martin Kamp, Lukas Worschech, and Alfred Forchel — Technische Physik, Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany

The realization of efficient single photon sources (SPSs) is a driving force in the development of quantum dot - microcavity structures. In fact, the outcoupling efficiency of a quantum dot (QD) can be strongly enhanced in the presence of a high quality microcavity providing three dimensional photon confinement. In this context, QD-micropillar cavities are of special interest due to predicted photon extraction efficiencies of up to 70%. In light of possible applications of SPSs, e.g. in quantum key distribution systems, and the associated device integration it is crucial to establish an electrical pumping scheme capable for high frequency operation.

We report on triggered single photon emission from low mode volume electrically driven quantum dot-micropillar cavities at repetition rates of up to 220 MHz. Due to an optimized layout of the doped planar microcavity and an advanced lateral current injection scheme, highly efficient single photon sources are realized. While g⁽²⁾(0)-values as low as 0.13±0.05 and a Purcell-factor of 4 are observed for a 2 µm diameter micropillar, single photon emission at a rate of (35±7) MHz and an overall efficiency of (34±7)% are demonstrated for a 3 µm device.