skip to main content

SciTech ConnectSciTech Connect

Title: The disorder-induced Raman scattering in Au/MoS{sub 2} heterostructures

The Raman scattering has been studied in heterostructures composed of a thin MoS{sub 2} flake and a 1-1.5 nm layer of thermally evaporated gold (Au). There have been Au nanoislands detected in the heterostructure. It has been found that their surface density and the average size depend on the MoS{sub 2} thickness. The Raman scattering spectrum in the heterostructure with a few monolayer MoS{sub 2} only weakly depends on the excitation (resonant vs. non-resonant) mode. The overall Raman spectrum corresponds to the total density of phonon states, which is characteristic for disordered systems. The disorder in the MoS{sub 2} layer is related to the mechanical strain induced in the MoS{sub 2} layer by the Au nanoislands. The strain results in the localization of phonon modes, which leads to the relaxation of the momentum conservation rule in the scattering process. The relaxation allows phonons from the whole MoS{sub 2} Brillouin zone to interact with electronic excitations. Our results show that the Au nanoislands resulted from thermal evaporation of a thin metal layer introduce substantial disorder into the crystalline structure of the thin MoS{sub 2} layers.
Authors:
; ; ; ; ;  [1]
  1. Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warszawa (Poland)
Publication Date:
OSTI Identifier:
22493940
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Advances; Journal Volume: 5; Journal Issue: 7; Other Information: (c) 2015 Author(s); Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; BRILLOUIN ZONES; CRYSTAL STRUCTURE; EVAPORATION; EXCITATION; GOLD; HETEROJUNCTIONS; LAYERS; MOLYBDENUM SULFIDES; PHONONS; RAMAN EFFECT; RAMAN SPECTRA; RELAXATION; STRAINS; SURFACES