Regensburg 2022 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 25: Poster 1
HL 25.30: Poster
Mittwoch, 7. September 2022, 18:00–20:00, P2
Charge carrier localization in nanobubbles of atomically thin TMD semiconductors — Christian Carmesin1, Michael Lorke1,2, Matthias Florian1, •Daniel Erben1, and Frank Jahnke1 — 1Institute for Theoretical Physics, University of Bremen — 2Bremen Center for Computational Materials Science, University of Bremen
Atomically thin transition metal dichalcogenides on nanostructured substrate like nanopillar arrays have gained attention as they show single photon emission. In contrast to a prestructured substrates, we investigate TMD nanobubbles that form naturally during stacking processes. Upon optical excitation these bubbles also exhibit quantum light emission, which indicates strong charge carrier confinement.
Starting from atomistic modelling of the strain field and electronic confinement potential of the nanobubble structure, we calculate the excitation spectrum for different bubble geometries. The microscopic origin of this carrier confinement lies in the bending rigidity of these materials leading to wrinkling of the surface. The resulting strain field facilitates nanoscale carrier localization due to its pronounced influence on the band gap. This localization mechanism is supported by local changes of the dielectric environment. As a result, strongly localized states are formed that lead to emission sites around the periphery of the nanobubble. A specific localization signature allows for experimental identification of this mechanism, which has also been demonstrated in spatially resolved photoluminescence experiments.