Tip-induced and electrical control of the photoluminescence yield of monolayer WS2
Résumé
Monolayer transition metal dichalcogenides (TMDs) are two-dimensional (2D) direct bandgap semiconductors that have the potential to lead to breakthrough applications in nanodevice technologies due to their unique optical and electronic properties (1). The photophysics of monolayer TMDs is governed by the dynamics of bound electron-hole pairs (i.e., excitons) and their interactions with charge carriers (2). Manipulating the creation, diffusion, and recombination of excitons is essential for the performance of monolayer TMD-based devices. In particular, locally controlling the radiative quantum yield and the formation of charged excitons (trions) in these
materials has been a long-sought-after goal. Attempts to achieve such nanoscale control have been reported, for example using the plasmonic tip of an atomic force microscope (3); however, such techniques do not provide any direct information about the local diffusion and recombination processes of these excitons, a key aspect for the integration of these materials into devices. Here, we present a novel method to locally and electrically control the radiative quantum yield of monolayer TMDs on a transparent electrode (indium tin oxide-coated glass) using a scanning tunneling microscope (STM) equipped with a tungsten tip.
Using a combination of STM and wide-field laser-induced photoluminescence microscopy (PL), we demonstrate and we spatially and spectrally resolve the reversible effects of the biased tip-sample junction on the excitonic properties of a WS2 monolayer (4).
REFERENCES
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2. G. Wang, A. Chernikov, M. M. Glazov, T. F. Heinz, X. Marie, T. Amand, B. Urbaszek, Rev.
Mod. Phys., 90, 021001 (2018)
3. Z. He et al, Sci. Adv., 5, eaau8763 (2019)
4. R. J. Peña Román et al, “Tip-induced and electrical control of the photoluminescence yield of
monolayer WS2”, submitted