Disentangling the effects of doping, strain and defects in monolayer WS2 by optical spectroscopy

Abstract

Monolayers of transition metal dichalcogenides (TMdC) are promising candidates for realization of a new generation of optoelectronic devices. The optical properties of these two-dimensional materials, however, vary from flake to flake, or even across individual flakes, and change over time, all of which makes control of the optoelectronic properties challenging. There are many different perturbations that can alter the optical properties, including charge doping, defects, strain, oxidation, and water intercalation. Identifying which perturbations are present is usually not straightforward and requires multiple measurements using multiple experimental modalities, which presents barriers when attempting to optimise preparation of these materials. Here, we apply highresolution photoluminescence and differential reflectance hyperspectral imaging in situ to CVD-grown WS2 monolayers. By combining these two optical measurements and using a statistical correlation analysis we are able to disentangle three contributions modulating optoelectronic properties of these materials: electron doping, strain and defects. In separating these contributions, we also observe that the B-exciton energy is less sensitive to variations in doping density than A-excitons.

arXiv comment27 pages, 5 figures

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Cited by in corpus (12)

• Direct Measurement of Biexcitons in Monolayer WS2
• Coherent Dynamics of Floquet-Bloch States in Monolayer WS2 Reveals Fast Adiabatic Switching
• Photophysical comparison of liquid and mechanically exfoliated WS${}_2$ monolayers
• Multidimensional Analysis of Excitonic Spectra of Monolayers of Tungsten Disulphide: Towards Computer Aided Identification of Structural and Environmental Perturbations of 2D Materials
• A simple KPFM-based approach for electrostatic-free topographic measurements: the case of MoS${}_2$ on SiO${}_2$
• Effects of Floquet Engineering on the Coherent Exciton Dynamics in Monolayer WS${}_2$
• Hyperspectral photoluminescence and reflectance microscopy of 2D materials
• Symmetric Domain Segmentation in WS2 Flakes: Correlating spatially resolved photoluminescence, conductance with valley polarization
• Extremely high excitonic $g$-factors in 2D crystals by alloy-induced admixing of band states
• Effect of manganese incorporation on the excitonic recombination dynamics in monolayer MoS${}_2$
• Floquet engineering in the presence of optically excited carriers
• Subnanometric control of coupling between WS${}_2$ monolayers with a molecular spacer