Plasmonic Pumping of Excitonic Photoluminescence in Hybrid MoS sub(2)-Au Nanostructures

• Published in: ACS nano Vol. 8; no. 12; pp. 12682 - 12689
• Main Authors: Najmaei, Sina, Mlayah, Adnen, Arbouet, Arnaud, Girard, Christian, Leotin, Jean, Lou, Jun
• Format: Journal Article
• Language: English
• Published: 03-02-2014
• Subjects: Excitation; Molybdenum disulfide; Monolayers; Nanostructure; Optical pumping; Photoluminescence; Plasmonics; Semiconductors
• DOI: 10.1021/nn5056942
• EISSN: 1936-086X
• ISSN: 1936-0851

We report on the fabrication of monolayer MoS sub(2)-coated gold nanoantennas combining chemical vapor deposition, e-beam lithography surface patterning, and a soft lift-off/transfer technique. The optical properties of these hybrid plasmonic-excitonic nanostructures are investigated using spatially resolved photoluminescence spectroscopy. Off- and in-resonance plasmonic pumping of the MoS sub(2) excitonic luminescence showed distinct behaviors. For plasmonically mediated pumping, we found a significant enhancement ( similar to 65%) of the photoluminescence intensity, clear evidence that the optical properties of the MoS sub(2) monolayer are strongly influenced by the nanoantenna surface plasmons. In addition, a systematic photoluminescence broadening and red-shift in nanoantenna locations is observed which is interpreted in terms of plasmonic enhanced optical absorption and subsequent heating of the MoS sub(2) monolayers. Using a temperature calibration procedure based on photoluminescence spectral characteristics, we were able to estimate the local temperature changes. We found that the plasmonically induced MoS sub(2) temperature increase is nearly four times larger than in the MoS sub(2) reference temperatures. This study shines light on the plasmonic-excitonic interaction in these hybrid metal/semiconductor nanostructures and provides a unique approach for the engineering of optoelectronic devices based on the light-to-current conversion. Keywords: plasmonic; photoluminescence; nanostructure