Enhanced Light Absorption and Efficient Carrier Collection in MoS2 Monolayers on Au Nanopillars

Jungeun Song, Soyeong Kwon, Hyunjeong Jeong, Hyeji Choi, Anh Thi Nguyen, Ha Kyung Park, Hyeong Ho Park, William Jo, Sang Wook Lee, Dong Wook Kim

Research output: Contribution to journalArticlepeer-review

Abstract

We fabricated hybrid nanostructures consisting of MoS2 monolayers and Au nanopillar (Au-NP) arrays. The surface morphology and Raman spectra showed that the MoS2 flakes transferred onto the Au-NPs were very flat and nonstrained. The Raman and photoluminescence intensities of MoS2/Au-NP were 3-and 20-fold larger than those of MoS2 flakes on a flat Au thin film, respectively. The finite-difference time-domain calculations showed that the Au-NPs significantly concentrated the incident light near their surfaces, leading to broadband absorption enhancement in the MoS2 flakes. Compared with a flat Au thin film, the Au-NPs enabled a 6-fold increase in the absorption in the MoS2 monolayer at a wavelength of 615 nm. The contact potential difference mapping showed that the electric potential at the MoS2/Au contact region was higher than that of the suspended MoS2 region by 85 mV. Such potential modulation enabled the Au-NPs to efficiently collect photogenerated electrons from the MoS2 flakes, as revealed by the uniform positive surface photovoltage signals throughout the MoS2 surface.

Original languageEnglish
Article number1567
JournalNanomaterials
Volume12
Issue number9
DOIs
StatePublished - 1 May 2022

Keywords

  • electron transfer
  • MoS
  • photoluminescence
  • surface photovoltage
  • surface plasmon

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