Dresden 2006 – wissenschaftliches Programm
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HL: Halbleiterphysik
HL 52: Quantum dots and wires: Optical properties IV
HL 52.11: Vortrag
Freitag, 31. März 2006, 13:30–13:45, POT 151
Lasing effects in high quality AlAs/GaAs micropillar cavities — •Carolin Hofmann1, Stephan Reitzenstein1, Steffen Münch1, Anatolly Bazhenov1,2, Alexander Gorbunov1,2, Andreas Löffler1, Johann Peter Reithmaier1,3, Martin Kamp1, Leonid Keldysh1,4, Vladimir Kulakovskii1,2, and Alfred Forchel1 — 1Technische Physik, Universität Würzburg, Germany — 2Institute for Solid State Physics, Russian Academy of Science, Chernogolovka, Russia — 3Physik, Universität Kassel, Germany — 4Lebedev Physical Institute, Russian Academy of Science, Moscow, Russia
We report on studies performed on optically pumped high quality micropillar laser-structures. The pillars are based on planar microcavity structures grown by molecular beam epitaxy. The planar structures consist of a GaAs λ-cavity sandwiched between DBR with up to 27 quarter-wavelength layer pairs of AlAs and GaAs. In the center of the cavity a low density layer of InGaAs quantum dots is embedded. Micropillars with diameters as low as a few hundred nanometers were patterned. By microphotoluminecence measurements at low temperatures we have studied the transition from spontaneous emission to laser operation for pillars of different diameter and quality factors of up to 35000. Lasing was observed for pillars which contain less than 100 quantum dots. Laser operation is identified by a nonlinear increase of the output intensity versus excitation power. We will discuss the influence of the pillar diameter and the quality factor on the lasing characteristics of the micropillar laser-structures and give an estimation of the influence of single quantum dots on the lasing behaviour.