Optimum absorption of MoS2 monolayer using Cavity Resonator Integrated Filtering
Résumé
Transition Metal Dichalcogenides (TMD) are two-dimensional (2D) semiconductor materials with astonishing physical and especially optical properties [1] thanks to their stunning excitonic binding energy [2] . In order to exploit these promising optical properties for applications, this work explores the conception and fabrication of hybrid photonic devices based on the integration of a MoS 2 monolayer in photonic structures. To enhance the photocurrent (PC) and photoluminescence (PL) of MoS 2 monolayer, the latter is incorporated into photonic cavities designed to achieve a maximum optical absorption by the TMD layer at a target excitation wavelength. Numerical simulations based on the scattering matrix method [3] , [4] are used to explore the optical properties of these hybrid structures combining micro and nanoscale engineering. Figure 1.a shows the typical studied stack consisting of a Grating-Mode Resonant Filter (GMRF) structure with a planar guiding layer fabricated on a monolayer of MoS 2 deposited or transferred onto silicon oxide film with a back side metallic mirror forming a vertical cavity. The optimisation of the layer thicknesses and parameters of the GMRF led to the selection of a particular structure which allows to achieve more than 97% of absorption of the incident light at 532 nm in the MoS 2 monolayer as shown in Figure 1.b . To reduce the lateral extension of the optical structure while maintaining high absorption in the TMD, the simple GMRF can be replaced by a Cavity Resonator Integrated Filter (CRIGF) [5] to combine vertical and horizontal optical confinements. With this hybrid TMD/photonic structure, 90% of the incident light at 532 nm is absorbed by the MoS 2 monolayer.
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