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 WS2 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 WS2. 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.
@article{arxiv.2001.05481,
title = {Neutral and charged excitons interplay in non-uniformly strain-engineered WS$_2$},
author = {Sviatoslav Kovalchuk and Moshe G. Harats and Guillermo López-Polín and Jan N. Kirchhof and Katja Höflich and Kirill I. Bolotin},
journal= {arXiv preprint arXiv:2001.05481},
year = {2025}
}