Tip-Induced and Electrical Control of the Photoluminescence Yield of Monolayer WS<sub>2</sub>.
basic_science · Level V
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- Record sourced from PubMed, PMID 36458911.
- Also identified by DOI 10.1021/acs.nanolett.2c02142.
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Abstract
The photoluminescence (PL) of monolayer tungsten disulfide (WS<sub>2</sub>) is locally and electrically controlled using the nonplasmonic tip and tunneling current of a scanning tunneling microscope (STM). The spatial and spectral distribution of the emitted light is determined using an optical microscope. When the STM tip is engaged, short-range PL quenching due to near-field electromagnetic effects is present, independent of the sign and value of the bias voltage applied to the tip-sample tunneling junction. In addition, a bias-voltage-dependent long-range PL quenching is measured when the sample is positively biased. We explain these observations by considering the native n-doping of monolayer WS<sub>2</sub> and the charge carrier density gradients induced by electron tunneling in micrometer-scale areas around the tip position. The combination of wide-field PL microscopy and charge carrier injection using an STM opens up new ways to explore the interplay between excitons and charge carriers in two-dimensional semiconductors.