Optical control of charged exciton states in tungsten disulfide

Abstract

A method is presented for optically preparing WS2 monolayers to luminesce from only the charged exciton (trion) state--completely suppressing the neutral exciton. When isolating the trion state, we observed changes in the Raman A1g intensity and an enhanced feature on the low energy side of the E12g peak. Photoluminescence and optical reflectivity measurements confirm the existence of the prepared trion state. This technique also prepares intermediate regimes with controlled luminescence amplitudes of the neutral and charged exciton. This effect is reversible by exposing the sample to air, indicating the change is mitigated by surface interactions with the ambient environment. This method provides a tool to modify optical emission energy and to isolate physical processes in this and other two-dimensional materials.

13 pages, 4 Figures, 32 references

References in corpus (3)

• Strong Photoluminescence Enhancement of MoS2 through Defect Engineering and Oxygen Bonding
• Electrical Transport Properties of Single-Layer WS2
• Measurement of high exciton binding energy in the monolayer transition-metal dichalcogenides WS2 and WSe2

Cited by in corpus (15)

• Excitonic linewidth approaching the homogeneous limit in MoS2 based van der Waals heterostructures : accessing spin-valley dynamics
• The Effect of Preparation Conditions on Raman and Photoluminescence of Monolayer WS2
• Near-unity light absorption in a monolayer WS2 van der Waals heterostructure cavity
• Room temperature observation of biexcitons in exfoliated WS2 monolayers
• Ultra-low power threshold for laser induced changes in optical properties of 2D Molybdenum dichalcogenides
• Anomalous temperature-dependent spin-valley polarization in monolayer WS${}_2$
• Prominent room temperature valley polarization in WS2/graphene heterostructures grown by chemical vapor deposition
• Spectrally narrow exciton luminescence from monolayer MoS2 exfoliated onto epitaxially grown hexagonal BN
• Modulation of trion and exciton formation in monolayer WS2 by dielectric and substrate engineering
• Effects of CVD Growth Parameters on Global and Local Optical Properties of MoS${}_2$ Monolayers
• Variation of photoluminescence spectral line shape of monolayer WS2
• Spatial Non-Uniformity in Exfoliated WS2 Single layers
• Long-lived spin polarization in n-doped MoSe${}_2$ monolayers
• Microscopic model of the doping dependence of line widths in monolayer transition metal dichalcogenides
• $\Gamma$-valley assisted intervalley scattering on monolayer and bilayer WS2 revealed by time-resolved Kerr rotation spectroscopy