Opto-valleytronic imaging of atomically thin semiconductors

Abstract

Transition metal dichalcogenide semiconductors represent elementary components of layered heterostructures for emergent technologies beyond conventional opto-electronics. In their monolayer form they host electrons with quantized circular motion and associated valley polarization and valley coherence as key elements of opto-valleytronic functionality. Here, we introduce two-dimensional polarimetry as means of direct imaging of the valley pseudospin degree of freedom in monolayer transition metal dichalcogenides. Using MoS${}_2$ as a representative material with valley-selective optical transitions, we establish quantitative image analysis for polarimetric maps of extended crystals, and identify valley polarization and valley coherence as sensitive probes of crystalline disorder. Moreover, we find site-dependent thermal and non-thermal regimes of valley-polarized excitons in perpendicular magnetic fields. Finally, we demonstrate the potential of wide-field polarimetry for rapid inspection of opto-valleytronic devices based on atomically thin semiconductors and heterostructures.

References in corpus (12)

• Valley polarization in MoS2 monolayers by optical pumping
• The Valley Hall Effect in MoS2 Transistors
• Valley filter and valley valve in graphene
• Magnetic Control of Valley Pseudospin in Monolayer WSe2
• Valley Zeeman Effect in Elementary Optical Excitations of a Monolayer WSe2
• Breaking of valley degeneracy by magnetic field in monolayer MoSe2
• Non-linear Optical Spectroscopy of Excited Exciton States for Efficient Valley Coherence Generation in WSe2 Monolayers
• Valley Splitting and Polarization by the Zeeman Effect in Monolayer MoSe2
• Robust optical emission polarization in MoS2 monolayers through selective valley excitation
• Ultrafast Generation of Pseudo-magnetic Field for Valley Excitons in WSe2 Monolayers
• Topological Polaritons
• Magneto-optics in transition metal diselenide monolayers

Cited by in corpus (6)

• Spin-Valley Locking Effect in Defect States of Monolayer MoS${}_2$
• Excitons in mesoscopically reconstructed moiré heterostructures
• Valley Degree of Freedom in Two-Dimensional van der Waals Materials
• Spatiotemporal dynamics of free and bound excitons in CVD-grown MoS${}_2$ monolayer
• Signatures of defect-localized charged excitons in the photoluminescence of monolayer molybdenum disulfide
• Spin polarization in Lateral two-dimensional Heterostructures