Simultaneous Existence of Confined and Delocalized Vibrational Modes in Colloidal Quantum Dots

Coupling to phonon modes is a primary mechanism of excitonic dephasing and energy loss in semiconductors. However, low-energy phonons in colloidal quantum dots and their coupling to excitons are poorly understood, since their experimental signatures are weak and usually obscured by unavoidable inhom...

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Bibliographic Details
Published inarXiv.org
Main Authors Liu, Albert, Almeida, Diogo B, Wan-Ki Bae, Padilha, Lazaro A, Cundiff, Steven T
Format Paper Journal Article
LanguageEnglish
Published Ithaca Cornell University Library, arXiv.org 23.07.2019
Subjects
Cadmium selenides
Colloids
Coupling
Cryogenic temperature
Electrons
Energy dissipation
Excitons
Nonlinear response
Phonons
Physics - Materials Science
Physics - Mesoscale and Nanoscale Physics
Quantum dots
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Summary:Coupling to phonon modes is a primary mechanism of excitonic dephasing and energy loss in semiconductors. However, low-energy phonons in colloidal quantum dots and their coupling to excitons are poorly understood, since their experimental signatures are weak and usually obscured by unavoidable inhomogeneous broadening of colloidal dot ensembles. We use multi-dimensional coherent spectroscopy at cryogenic temperatures to extract the homogeneous nonlinear optical response of excitons in a CdSe/CdZnS core/shell colloidal quantum dot ensemble. Comparison to simulation provides evidence that the observed lineshapes arise from the co-existence of confined and delocalized vibrational modes, both of which couple strongly to excitons in CdSe/CdZnS colloidal quantum dots.
ISSN:2331-8422
DOI:10.48550/arxiv.1907.09889