Neutral and charged excitons interplay in non-uniformly strain-engineered WS2
| Autor: | Moshe G. Harats, Sviatoslav Kovalchuk, Jan N. Kirchhof, Katja Höflich, Guillermo López-Polín, Kirill I. Bolotin |
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| Rok vydání: | 2020 |
| Předmět: |
Photoluminescence
Materials science Condensed matter physics Strain (chemistry) Mechanical Engineering Exciton 02 engineering and technology General Chemistry 021001 nanoscience & nanotechnology Condensed Matter Physics 01 natural sciences Strain engineering Mechanics of Materials 0103 physical sciences General Materials Science Trion 010306 general physics 0210 nano-technology |
| Zdroj: | 2D Materials |
| ISSN: | 2053-1583 0953-8984 |
| DOI: | 10.1088/2053-1583/ab8caa |
| Popis: | We investigate the response of excitons in two-dimensional semiconductors to nonuniformity of mechanical strain. In our approach to non-uniform strain-engineering, a WS2 monolayer is suspended over a triangular hole. Large (>2%), strongly non-uniform (>0.28% µm–1), and in-situ tunable strain is induced in WS2 by pressurizing it with inert gas. We observe a pronounced shift of the spectral weight from neutral to charged excitons at the center of the membrane, in addition to well-known strain-dependent bandgap modification. We show that the former phenomenon is a signature of a new effect unique for non-uniform strain: funneling of free carriers towards the region of high strain followed by neutral to charged exciton conversion. Our result establishes non-uniform strain engineering as a novel and useful experimental ‘knob’ for tuning optoelectronic properties of 2D semiconductors. |
| Databáze: | OpenAIRE |
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