Opposite Polarity Surface Photovoltage of MoS2Monolayers on Au Nanodot versus Nanohole Arrays

Jungeun Song, Soyeong Kwon, Bora Kim, Eunah Kim, Lakshmi N.S. Murthy, Taejin Lee, Inhae Hong, Byoung Hoon Lee, Sang Wook Lee, Soo Ho Choi, Ki Kang Kim, Chang Hee Cho, Julia W.P. Hsu, Dong Wook Kim

Research output: Contribution to journalArticlepeer-review

8 Scopus citations

Abstract

We prepared MoS2 monolayers on Au nanodot (ND) and nanohole (NH) arrays. Both these sample arrays exhibited enhanced photoluminescence intensity compared with that of a bare SiO2/Si substrate. The reflectance spectra of MoS2/ND and MoS2/NH had clear features originating from excitation of localized surface plasmon and propagating surface plasmon polaritons. Notably, the surface photovoltages (SPV) of these hybrid plasmonic nanostructures had opposite polarities, indicating negative and positive charging at MoS2/ND and MoS2/NH, respectively. Surface potential maps, obtained by Kelvin probe force microscopy, suggested that the potential gradient led to a distinct spatial distribution of photo-generated charges in these two samples under illumination. Furthermore, the local density of photo-generated excitons, as predicted from optical simulations, explained the SPV spectra of MoS2/ND and MoS2/NH. We show that the geometric configuration of the plasmonic nanostructures modified the polarity of photo-generated excess charges in MoS2. These findings point to a useful means of optimizing optoelectronic characteristics and improving the performance of MoS2-based plasmonic devices.

Original languageEnglish
Pages (from-to)48991-48997
Number of pages7
JournalACS Applied Materials and Interfaces
Volume12
Issue number43
DOIs
StatePublished - 28 Oct 2020

Keywords

  • MoS
  • localized surface plasmon
  • photoluminescence
  • surface photovoltage
  • surface plasmon polariton

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