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arXiv · 1507.01342

Identification of excitons, trions and biexcitons in single-layer WS2

Gerd Plechinger·Philipp Nagler·Julia Kraus·Nicola Paradiso·Christoph Strunk·Christian Schüller·Tobias Korn
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Abstract

Single-layer WS$_2$ is a direct-gap semiconductor showing strong excitonic photoluminescence features in the visible spectral range. Here, we present temperature-dependent photoluminescence measurements on mechanically exfoliated single-layer WS$_2$, revealing the existence of neutral and charged excitons at low temperatures as well as at room temperature. By applying a gate voltage, we can electrically control the ratio of excitons and trions and assert a residual n-type doping of our samples. At high excitation densities and low temperatures, an additional peak at energies below the trion dominates the photoluminescence, which we identify as biexciton emission.

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Gerd Plechinger, Philipp Nagler, Julia Kraus, Nicola Paradiso, Christoph Strunk, Christian Schüller, Tobias Korn. 2015-07-22. Identification of excitons, trions and biexcitons in single-layer WS2. https://doi.org/10.1002/pssr.201510224

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