Dresden 2011 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 7: Single Photon Sources and Qbits
HL 7.3: Talk
Monday, March 14, 2011, 11:30–11:45, FOE Anorg
Single photon emission from ultralow density InP/GaInP quantum dots — •Stefan Kremling1, Asli Ugur2, Sven Höfling1, Lukas Worschech1, Fariba Hatami2, Ted Masselink2, and Alfred Forchel1 — 1Technische Physik, Wilhelm Conrad Röntgen Research Center for Complex Material Systems, Physikalisches Institut, Universität Würzburg, Am Hubland, D-97074 Würzburg — 2Department of Physics, Humbold Universität zu Berlin, Newtonstrasse 15, D-12489 Berlin
We have investigated ultralow-density InP quantum dots (QDs) in In0,48Ga0,52P. The QDs were grown using gas-source molecular-beam epitaxy (GSMBE) with ultralow growth rate. InP QDs emitting in the visible red spectral range and therefore they are ideal candidates for free space single photon applications, as Si avalanche photodiodes (APD) have their maximum efficiency in this spectral region.
Autocorrelation measurements under cw excitation were performed with a single QD and a pronounced antibunching dip was observed. Furthermore we investigated the electronic structure and magneto-optical properties. In-plane anisotropy will reduce the point group symmetry and therefore annihilate the spin degeneration and the bright exciton doublet splits into two linearly combined states, separated by a fine structure splitting. At zero magnetic field, the quantum dots show a large perpendicular linearly polarized fine structure splitting up to 320 µ eV. Magneto-optical measurements in Faraday geometry exhibit a diamagnetic shift of 4 µ eV/T2 and Zeeman splitting with an effective exciton g-factor of ≈ 1.