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HL: Fachverband Halbleiterphysik
HL 63: Poster: Quantum Dots and Optics
HL 63.62: Poster
Wednesday, March 22, 2017, 15:00–19:00, P1A
Epitaxial growth and characterization of InP-based coupled quantum well - quantum dot structures — •Sven Bauer1, Vitalii Sichkovskyi1, Wojciech Rudno-Rudziński2, Grzegorz Sek2, and Johann Peter Reithmaier1 — 1Technische Physik, Institute of Nanostructure Technologies and Analytics (INA), CINSaT, University of Kassel, Heinrich-Plett-Str. 40, 34132 Kassel, Germany — 2Institute of Physics, Wrocław University of Technology, Wybrzeze Wyspiańskiego 27, 50-370 Wrocław, Poland
InP-based directly modulated quantum dot (QD) lasers are promising candidates for usage in telecommunication at 1.55 µm. In order to improve the performance of these lasers, limited by the intraband carrier relaxation time, one might use a so called tunnel injection scheme. Carriers are captured and relax in a quantum well (QW) and tunnel through a thin barrier for recombination into the QDs. In order to get better understanding of the mechanisms involved in this scheme, coupled QW-QD structures have been grown on Fe-doped InP substrates. These consist of a compressively strained In0.66Ga0.34As QW and InAs QDs separated by a thin InAlGaAs barrier. High density QD growth was optimized beforehand. A set of samples with different QW (2.4 nm, 4 nm, 5.6 nm) and barrier thickness (2 nm, 4 nm, 10 nm) combinations was grown and investigated with photoluminescence and photoreflectance spectroscopy. The working principle with respect to coupling strength as well as the importance of a favourable band alignment for performance and dominating recombination channel could be shown.