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Title: Electron-phonon interactions in MoS{sub 2} probed with ultrafast two-dimensional visible/far-infrared spectroscopy

An ultrafast two-dimensional visible/far-IR spectroscopy based on the IR/THz air biased coherent detection method and scanning the excitation frequencies is developed. The method allows the responses in the far-IR region caused by various electronic excitations in molecular or material systems to be observed in real time. Using the technique, the relaxation dynamics of the photo-excited carriers and electron/phonon coupling in bulk MoS{sub 2} are investigated. It is found that the photo-generation of excited carriers occurs within two hundred fs and the relaxation of the carriers is tens of ps. The electron-phonon coupling between the excitations of electrons and the phonon mode E{sub 1u} of MoS{sub 2} is also directly observed. The electron excitation shifts the frequency of the phonon mode 9 cm{sup −1} higher, resulting in an absorption peak at 391 cm{sup −1} and a bleaching peak at 382 cm{sup −1}. The frequency shift diminishes with the relaxation of the carriers.
Authors:
; ; ;  [1]
  1. Department of Chemistry, Rice University, 6100 Main Street, Houston, Texas 77005-1892 (United States)
Publication Date:
OSTI Identifier:
22415914
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Chemical Physics; Journal Volume: 142; Journal Issue: 21; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; ABSORPTION SPECTROSCOPY; BLEACHING; DETECTION; ELECTRON-PHONON COUPLING; ELECTRONS; EXCITATION; INFRARED SPECTRA; MOLYBDENUM SULFIDES; PHONONS; PROBES; RELAXATION; TWO-DIMENSIONAL SYSTEMS