Neutral and charged excitons interplay in non-uniformly strain-engineered WS$_2$
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| Main Authors: | , , , , , |
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| Format: | Preprint |
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2020
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| _version_ | 1866917013654339584 |
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| author | Kovalchuk, Sviatoslav Harats, Moshe G. López-Polín, Guillermo Kirchhof, Jan N. Höflich, Katja Bolotin, Kirill I. |
| author_facet | Kovalchuk, Sviatoslav Harats, Moshe G. López-Polín, Guillermo Kirchhof, Jan N. Höflich, Katja Bolotin, Kirill I. |
| contents | We investigate the response of excitons in two-dimensional semiconductors subjected to controlled non-uniform strain fields. In our approach to non-uniform strain-engineering, a WS$_2$ monolayer is suspended over a triangular hole. Large ($>2\;\%$), strongly non-uniform ($>0.28\;\%/μm$), and in-situ tunable strain is induced in the monolayer by pressurizing it with inert gas. We observe peak shifts and spectral shape changes in the photoluminescence spectra of strained WS$_2$. We interpret these changes as a signature of increased free electron density and resulting conversion of neutral excitons to trions in the region of high strain. Our result establishes non-uniform strain engineering as a novel and useful experimental `knob' for tuning optoelectronic properties of 2D semiconductors. |
| format | Preprint |
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arxiv_https___arxiv_org_abs_2001_05481 |
| institution | arXiv |
| publishDate | 2020 |
| record_format | arxiv |
| spellingShingle | Neutral and charged excitons interplay in non-uniformly strain-engineered WS$_2$ Kovalchuk, Sviatoslav Harats, Moshe G. López-Polín, Guillermo Kirchhof, Jan N. Höflich, Katja Bolotin, Kirill I. Mesoscale and Nanoscale Physics We investigate the response of excitons in two-dimensional semiconductors subjected to controlled non-uniform strain fields. In our approach to non-uniform strain-engineering, a WS$_2$ monolayer is suspended over a triangular hole. Large ($>2\;\%$), strongly non-uniform ($>0.28\;\%/μm$), and in-situ tunable strain is induced in the monolayer by pressurizing it with inert gas. We observe peak shifts and spectral shape changes in the photoluminescence spectra of strained WS$_2$. We interpret these changes as a signature of increased free electron density and resulting conversion of neutral excitons to trions in the region of high strain. Our result establishes non-uniform strain engineering as a novel and useful experimental `knob' for tuning optoelectronic properties of 2D semiconductors. |
| title | Neutral and charged excitons interplay in non-uniformly strain-engineered WS$_2$ |
| topic | Mesoscale and Nanoscale Physics |
| url | https://arxiv.org/abs/2001.05481 |