Optical Properties and Polariton Confinement of Monolayer Molybdenum Disulfide on Silicon Nitride Microdisks

International Journal of Physics | Vol. 14, No. 9, September 2023 | pp. 65–72

DOI: 10.46882/2023/IJP/000161

Research Article

Title: Optical Properties and Polariton Confinement of Monolayer Molybdenum Disulfide on Silicon Nitride Microdisks

Names of Authors: Y. S. Kim¹, T. H. Nguyen²

Authors’ Affiliations:
¹ Department of Physics and Astronomy, Seoul National University, Seoul, South Korea
² Department of Physics, Vietnam National University, Hanoi, Vietnam

Abstract: Monolayer transition metal dichalcogenides have attracted significant interest due to their strong light-matter interactions and potential for integrated nanophotonic circuits. This study characterises the optical properties and exciton-polariton dynamics of monolayer molybdenum disulfide (MoS²) integrated onto silicon nitride microdisk resonators. The monolayer flakes were synthesized via chemical vapor deposition and transferred onto the waveguides using an optimized dry-transfer technique. We performed micro-photoluminescence and angle-resolved reflectivity measurements under mechanical tensile strains from 0.0% to 1.6% at a room temperature of 300 K. The unstrained monolayer coupled to the evanescent field of the microdisk exhibits strong absorption lines, confirming efficient whispering-gallery mode phase-coupling. Applying a 1.0% tensile strain shifts the exciton resonance energy from 1.85 eV to 1.79 eV, yielding a strain tuning factor of 60.0 meV/% strain. Time-resolved photoluminescence spectroscopy revealed a shortened polariton decay lifetime, dropping from 16.5 ps down to 5.2 ps due to the cavity Purcell effect. Our numerical models confirm that the localized electromagnetic field confinement within the core increases the exciton-photon coupling rate by 35.0%. These findings demonstrate that cavity-integrated strain engineering offers an effective route for controlling polaritonic states.

Keywords: Molybdenum disulfide; silicon nitride; photoluminescence; exciton dynamics; whispering-gallery modes; integrated photonics

Manuscript Timeline: Received: June 04, 2023; Revised: July 28, 2023; Accepted: August 18, 2023; Published: September 11, 2023

Citation: Kim, Y. S., & Nguyen, T. H. (2023). Optical Properties and Polariton Confinement of Monolayer Molybdenum Disulfide on Silicon Nitride Microdisks. International Journal of Physics, 14(9), 65–72.

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