Enhanced absorption of CVD grown molybdenum disulfide monolayers via surface plasmon resonance with silver nano-triangles

Abstract

© 2019 Optical Society of America. Transient reflection was performed on large-area chemical vapor deposition (CVD) grown monolayer MoS2 flakes with silver nano-triangles coated on the surface to characterize its modifications to the optical properties of MoS2. Broadband transient reflection was carried out over a range of different pump wavelengths to tune in and out of the plasmonic resonance band of the nano-triangles. Large enhancement in transient reflectivity was observed, which approximately followed the plasmon resonance spectrum of the nano-triangles. Finite-difference time-domain simulationswere performed to verify that there is an increased absorption due to local surface plasmon-induced near-field enhancements. We also report observation of the dynamics of the MoS2 exciton bleaching bands, which showed subtle differences in recombination dynamics related to the exciton-plasmon coupling strength for excitation on-resonance and off-resonance at the silver nano-triangles plasmonic band.