Berlin 2005 – wissenschaftliches Programm
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HL: Halbleiterphysik
HL 36: Quantenpunkte und -dr
ähte: Optische Eigenschaften III
HL 36.4: Vortrag
Montag, 7. März 2005, 10:45–11:00, TU P164
Purcell effect in exciton and biexciton recombination in the same quantum dot in micropillar cavites — •Stephan Reitzenstein1, Dimitri Krizhanovskii1,2, Grzegorz Sek1,3, Carolin Hofmann1, Maxim Makhonin1,2, Vladimir Kulakivskii2, and Alfred Forchel1 — 1Technische Physik, Universität Würzburg, Am Hubland, D-97074 Würzburg — 2Institute for Solid State Physics, Russian Academy of Science, Chernogolovka, 142432, Russia — 3Institute of Physics, Wrocław University of Technology, 50-370 Wrocław, Poland
We report on the investigation of single and two exciton states of a single quantum dot (QD) embedded in the active layer of a high finesse (Q = 4500) GaAs/AlAs micropillar cavity. The microcavity structure is composed of 20 (23) repetitions of λ/4-GaAs/AlAs (69 nm/82 nm) layers in the top (bottom) Bragg reflector. The active layer in the λ-GaAs cavity contains self-assembled In0.6Ga0.4As QDs (density ≈ 1010 cm−2) placed at the antinode of the on-axis resonant fundamental mode of planar cavity. By tuning the QD exciton and the QD biexciton on resonance with the optical mode we observe a strong, but identical enhancement of the emission by a factor of about 30. By model calculations of the measured intensity dependences including sidewall losses we determine a Purcell factor of about 8 in both cases. This is fully consistent with the model for the Purcell factor, which relates the enhancement of the radiative recombination only with parameters of the cavity and not with the characteristics of the particular transition studied.