The Role of Electronic and Phononic Excitation in the Optical Response of Monolayer WS2 after Ultrafast Excitation

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• 作者：Claudia RuppertAlexey Chernikov ; Heather M. Hill ; Albert F. Rigosi ; Tony F. Heinz
• 刊名：Nano Letters
• 出版年：2017
• 出版时间：February 8, 2017
• 年：2017
• 卷：17
• 期：2
• 页码：644-651
• 全文大小：493K
• ISSN：1530-6992

文摘

Transient changes of the optical response of WS₂ monolayers are studied by femtosecond broadband pump–probe spectroscopy. Time-dependent absorption spectra are analyzed by tracking the line width broadening, bleaching, and energy shift of the main exciton resonance as a function of time delay after the excitation. Two main sources for the pump-induced changes of the optical response are identified. Specifically, we find an interplay between modifications induced by many-body interactions from photoexcited carriers and by the subsequent transfer of the excitation to the phonon system followed by cooling of the material through the heat transfer to the substrate.