Abstract
Strain engineering is a powerful tool for tuning physical properties of 2D materials, including monolayer transition metal dichalcogenides
(TMDs)—direct bandgap semiconductors with strong excitonic response. Deformation of TMD monolayers allows inducing modulation of
exciton potential and, ultimately, creating single-photon emitters at desired positions. The performance of such systems is critically dependent
on the exciton energy profile and maximum possible exciton energy shift that can be achieved under local impact until the monolayer rupture.
Here, we study the evolution of two-dimensional exciton energy profile induced in a MoSe2 monolayer under incremental local indentation
until the rupture. We controllably stress the flake with an atomic force microscope tip and perform in situ spatiospectral mapping of the
excitonic photoluminescence in the vicinity of the indentation point. In order to accurately fit the experimental data, we combine numerical
simulations with a simple model of strain-induced modification of the local excitonic response and carefully account for the optical resolution
of the setup. This allows us to extract deformation, strain, and exciton energy profiles obtained at each indentation depth. The maximum
exciton energy shift induced by local deformation achieved at 300 nm indentation reaches the value of 36.5 meV and corresponds to 1.15%
strain of the monolayer. Our approach is a powerful tool for in situ characterization of local optomechanical properties of 2D direct bandgap
semiconductors with strong excitonic response.
Original language | English |
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Number of pages | 101126 |
Journal | APL Materials |
Volume | 7 |
Issue number | 10 |
DOIs | |
Publication status | Published - 1 Oct 2019 |
Other keywords
- Tvívídd
- Leiðarar (rafmagn)