Electron-phonon interactions in MoS2 probed with ultrafast two-dimensional visible/far-infrared spectroscopy
Abstract
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.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- May 22, 2015
- Source ID
- 10.1063/1.4921573
Entities
People
- Hailong Chen
- Junrong Zheng
- Xiewen Wen
- Xunmin Guo
Organizations
- Air Force Office of Scientific Research
- Rice University
- Robert A. Welch Foundation