Ultrafast Plasmonic Hot Electron Transfer in Au Nanoantenna/MoS2 Heterostructures

2D transition metal dichalcogenides are becoming attractive materials for novel photoelectric and photovoltaic applications due to their excellent optoelectric properties and accessible optical bandgap in the near-infrared to visible range. Devices utilizing 2D materials integrated with metal nanostructures have recently emerged as efficient schemes for hot electron-based photodetection. Metal-semiconductor heterostructures with low cost, simple procedure, and fast response time are crucial for the practical applications of optoelectric devices. In this paper, template-based sputtering method is used first to fabricate Au nanoantenna (NA)/MoS2 heterostructures with low cost, simple preparation, broad spectral response, and fast response time. Through the measurement of femtosecond pump-probe spectroscopy, it is demonstrated that plasmon-induced hot electron transfer takes place in the Au NA/MoS2 heterostructure on the order of 200 fs with an injected electron density of about 5.6 x 10(12) cm(-2). Moreover, the pump-power-dependent photoluminescence spectra confirm that the exciton energy of MoS2 can be enhanced, coupled, and reradiated by the Au NA. Such ultrafast plasmon-induced hot electron transfer in the metal-semiconductor heterostructure can enable novel 2D devices for light harvesting and photoelectric conversion.National Basic Research Program of China (973 Program) [2015CB932403]; National Science Foundation of China [11374023, 61422501, 11674012, 61521004]; Beijing Natural Science Foundation [L140007]; Foundation for the Author of National Excellent Doctoral Dissertation of PR China [201420]; National Program for Support of Top-notch Young ProfessionalsSCI(E)EIARTICLEzhyfang@pku.edu.cn356394-64012