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Donatas Zigmantas. Portrait.

Donatas Zigmantas

Professor

Donatas Zigmantas. Portrait.

Direct Visualization of Confinement and Many-Body Correlation Effects in 2D Spectroscopy of Quantum Dots

Author

  • Edoardo Amarotti
  • Zhengjun Wang
  • Albin Hedse
  • Nils Lenngren
  • Karel Žídek
  • Kaibo Zheng
  • Donatas Zigmantas
  • Tõnu Pullerits

Summary, in English

The size tunable color of colloidal semiconductor quantum dots (QDs) is probably the most elegant illustration of the quantum confinement effect. As explained by the simple “particle-in-a-box” model, the transition energies between the levels increase when the “box” becomes smaller. To investigate quantum confinement effects, typically a well-defined narrow size distribution of the nanoparticles is needed. In this contribution, how coherent electronic two-dimensional spectroscopy (2DES) can directly visualize the quantum size effect in a sample with broad size distribution of QDs is demonstrated. The method is based on two features of the 2DES – the ability to resolve inhomogeneous broadening and the capability to reveal correlations between the states. In QD samples, inhomogeneous spectral broadening is mainly caused by the size distribution and leads to elongated diagonal peaks of the spectra. Since the cross peaks correlate the energies of two states, they allow drawing conclusions about the size dependence of the corresponding states. It is also found that the biexciton binding energy changes between 3 and 8 meV with the QD size. Remarkably, the size dependence is non-monotonic with a clear minimum.

Department/s

  • Chemical Physics
  • NanoLund: Centre for Nanoscience
  • LTH Profile Area: Nanoscience and Semiconductor Technology
  • LU Profile Area: Light and Materials
  • LTH Profile Area: Photon Science and Technology
  • eSSENCE: The e-Science Collaboration

Publishing year

2024

Language

English

Publication/Series

Advanced Optical Materials

Volume

12

Issue

15

Document type

Journal article

Publisher

John Wiley & Sons Inc.

Topic

  • Condensed Matter Physics (including Material Physics, Nano Physics)
  • Atom and Molecular Physics and Optics

Keywords

  • 2D electronic spectroscopy
  • biexciton
  • binding energy
  • quantum dots
  • size dependence
  • ultrafast spectroscopy

Status

Published

ISBN/ISSN/Other

  • ISSN: 2195-1071