Exciton dephasing by phonon-induced scattering between bright exciton states in InP/ZnSe colloidal quantum dots

Vigneshwaran Chandrasekaran; Lorenzo Scarpelli; Francesco Masia; Paola Borri; Zeger Hens; Wolfgang Langbein

doi:10.1117/12.3022347

11 June 2024 Exciton dephasing by phonon-induced scattering between bright exciton states in InP/ZnSe colloidal quantum dots

Vigneshwaran Chandrasekaran, Lorenzo Scarpelli, Francesco Masia, Paola Borri, Zeger Hens, Wolfgang Langbein

Author Affiliations +

Proceedings Volume PC12992, Advances in Ultrafast Condensed Phase Physics IV; PC129920H (2024) https://doi.org/10.1117/12.3022347
Event: SPIE Photonics Europe, 2024, Strasbourg, France

Abstract

Decoherence or dephasing of the exciton is a central characteristic of a Quantum Dot (QD) that determines the minimum width of the exciton emission line and the purity of indistinguishable photon emission during exciton recombination. Here, we analyze exciton dephasing in colloidal InP/ZnSe QDs using transient four-wave mixing spectroscopy. We obtain a dephasing time of 23ps at a temperature of 5K, which agrees with the smallest linewidth of 50ueV we measure for the exciton emission of single InP/ZnSe QDs at 5K. By determining the dephasing time as a function of temperature, we find that exciton decoherence can be described as a phonon-induced, thermally activated process. The deduced activation energy of 0.32meV corresponds to the small splitting within the nearly isotropic bright exciton triplet of InP/ZnSe QDs, suggesting that the dephasing is dominated by phonon-induced scattering within the bright exciton triplet.

Conference Presentation

Citation Download Citation

Vigneshwaran Chandrasekaran, Lorenzo Scarpelli, Francesco Masia, Paola Borri, Zeger Hens, and Wolfgang Langbein "Exciton dephasing by phonon-induced scattering between bright exciton states in InP/ZnSe colloidal quantum dots", Proc. SPIE PC12992, Advances in Ultrafast Condensed Phase Physics IV, PC129920H (11 June 2024); https://doi.org/10.1117/12.3022347

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