Open AccessElectron-phonon interactions in MoS2 probed with ultrafast two-dimensional visible/far-infrared spectroscopy
Author(s) -
Xunmin Guo,
Hailong Chen,
Xiewen Wen,
Junrong Zheng
Publication year - 2015
Publication title -
the journal of chemical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.071
H-Index - 357
eISSN - 1089-7690
pISSN - 0021-9606
DOI - 10.1063/1.4921573
Subject(s) - excited state , phonon , relaxation (psychology) , spectroscopy , electron , ultrashort pulse , far infrared , excitation , charge carrier , materials science , atomic physics , terahertz radiation , coupling (piping) , molecular physics , absorption (acoustics) , infrared , chemistry , condensed matter physics , physics , optics , optoelectronics , laser , psychology , social psychology , quantum mechanics , composite material , metallurgy
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 MoS2 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 E1u of MoS2 is also directly observed. The electron excitation shifts the frequency of the phonon mode 9 cm−1 higher, resulting in an absorption peak at 391 cm−1 and a bleaching peak at 382 cm−1. The frequency shift diminishes with the relaxation of the carriers
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