Berlin 2018 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 24: Poster Session II
HL 24.22: Poster
Dienstag, 13. März 2018, 18:30–20:30, Poster F
Recombination dynamics of InGaAsSb/GaP quantum dots — •Petr Steindl1,2, Petr Petr Klenovský1,2, Elisa Maddalena Sala3, Benito Alén4, and Dieter Bimberg3 — 1Department of Condensed Matter Physics, Faculty of Science, Masaryk University, Kotlářská 2, 61137 Brno, Czech Republic — 2Central European Institute of Technology, Masaryk University, Kamenice 753/5, 62500 Brno, Czech Republic — 3Institut für Festkörperphysik Technische Universität Berlin, Hardenbergstraße 36 10623 Berlin, Germany — 4Instituto de Micro y Nanotecnología, IMN-CNM, CSIC Isaac Newton, 8 PTM Tres Cantos 28760 Madrid, Spain
We examined the dynamics of optical transitions in ensemble InGaAsSb/GaP quantum dot samples by time-resolved photoluminescence spectroscopy. The studied dots provide a simultaneous occurrence of direct and indirect optical transitions. We focused on discerning those for the dominant dot emission band around 700 nm (1.77 eV) by performing time-resolved measurements for different wavelengths, sample temperatures and excitation intensities. We fit the time-resolved data by a double exponential model characterizing two separate recombination processes with average lifetimes of 60 ns and 10 ns. For the former we observe a considerable decrease of lifetime with temperature and we attribute that to spatially indirect transitions in quantum dots. On the other hand, lifetime of the latter transition does not appreciably depend on temperature and is probably connected with bulk recombinations.