Strain-dependent luminescence and piezoelectricity in monolayer transition metal dichalcogenides

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Date

2020-07-06

Authors

De Palma, Alex C.
Cossio, Gabriel
Jones, Kayleigh
Quan, Jiamin
Li, Xiaoqin
Yu, Edward T.

Journal Title

Journal ISSN

Volume Title

Publisher

AIP Publishing

Abstract

The modification of optical and electronic properties of transition metal dichalcogenides via mechanical deformation has been widely studied. Their ability to withstand large deformations before rupture has enabled large tunability of the bandgap, and further, the spatially varying strain has been shown to control the spatial distribution of the bandgap and lead to effects such as carrier funneling. Monolayer transition metal dichalcogenides exhibit a significant piezoelectric effect that could couple to a spatially inhomogeneous strain distribution to influence electronic and optical behavior. We investigate both experimentally and theoretically an example case of photoluminescence in structures with a strain distribution similar to that employed in single-photon emitters but generated here via nanoindentation. Using a mechanical model for strain induced by nanoindentation, we show that piezoelectricity can result in charge densities reaching 10

12 e/cm2 and can generate electrostatic potential variations on the order of ±0.1 V across the suspended monolayer. We analyze the implications of these results for luminescence and exciton transport in monolayer transition metal dichalcogenides with spatially varying strain.

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Citation

Alex C. De Palma, Gabriel Cossio, Kayleigh Jones, Jiamin Quan, Xiaoqin Li, Edward T. Yu; Strain-dependent luminescence and piezoelectricity in monolayer transition metal dichalcogenides. J. Vac. Sci. Technol. B 1 July 2020; 38 (4): 042205. https://doi.org/10.1116/6.0000251