Probing Interlayer Interactions in Transition Metal Dichalcogenide Heterostructures by Optical Spectroscopy: MoS2/WS2 and MoSe2/WSe2

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• 作者：Albert F. Rigosi ; Heather M. Hill ; Yilei Li ; Alexey Chernikov ; Tony F. Heinz
• 刊名：Nano Letters
• 出版年：2015
• 出版时间：August 12, 2015
• 年：2015
• 卷：15
• 期：8
• 页码：5033-5038
• 全文大小：302K
• ISSN：1530-6992

文摘

We have applied optical absorption spectroscopy to investigate van der Waals heterostructures formed of pairs of monolayer transition metal dichalcogenide crystals, choosing MoS₂/WS₂ and MoSe₂/WSe₂ as test cases. In the heterostructure spectra, we observe a significant broadening of the excitonic transitions compared to the corresponding features in the isolated layers. The broadening is interpreted as a lifetime effect arising from decay of excitons initially created in either layer through charge transfer processes expected for a staggered band alignment. The measured spectral broadening of 20 meV 鈥?35 meV implies lifetimes for charge separation of the near band-edge A and B excitons in the range of 20鈥?5 fs. Higher-lying transitions exhibit still greater broadening.