Regensburg 2022 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 39: Quantum Dots and Wires 6: II-VI and related

HL 39.2: Vortrag

Freitag, 9. September 2022, 09:45–10:00, H32

Collective Properties of CdSe-CdS giant-shell Quantum Dots — •Yannic Stächelin¹, Artur Feld¹, Agnes Weimer¹, Michael Deffner^2,3, Sonja Krohn⁴, Jan Steffen Niehaus⁴, and Holger Lange^1,3 — ¹Institut für Physikalische Chemie, Universität Hamburg, Hamburg, Germany — ²Institut für Anorganische und Angewandte Chemie, Universität Hamburg, Hamburg, Germany — ³The Hamburg Centre for Ultrafast Imaging, Hamburg, Germany — ⁴Fraunhofer IAP-CAN, Hamburg, Germany

CdSe-CdS core-giant-shell QDs are nowadays available with near-unity quantum yields, which makes them interesting candidates for lasing or display applications. Bright, high-PLQY QDs might also contribute to photonic quantum technologies as building blocks. QDs can realize deterministic photon-emitters and enable key quantum photonic resources and functionalities. Interaction of densely packed QDs can lead to collective phenomena like excitonic and photonic coupling, superfluorescence and enhanced quantum coherence. Incoherent dephasing processes may deteriorate the inherent quantum properties of QDs. We investigate dependencies of exciton formation in CdSe-CdS giant-shell QDs and interaction in dense ensembles of QDs via ultrafast THz and transient absorption spectroscopy. Polymer-micelles are used to produce dense ensembles containing a variable amount of QDs. In dense ensembles, we observe the onset of a collective dynamic depending on the excitation conditions, which are thus a means of controlling the dynamics.