Ultrafast formation of interlayer hot excitons in atomically thin MoS 2 /WS 2 heterostructures

Hailong Chen, Xiewen Wen, Jing Zhang, Tianmin Wu, Yongji Gong, Xiang Zhang, Jiangtan Yuan, Chongyue Yi, Jun Lou, Pulickel M. Ajayan, Wei Zhuang, Guangyu Zhang, Junrong Zheng

Research output: Journal article publicationJournal articleAcademic researchpeer-review

339 Citations (Scopus)

Abstract

Van der Waals heterostructures composed of two-dimensional transition-metal dichalcogenides layers have recently emerged as a new family of materials, with great potential for atomically thin opto-electronic and photovoltaic applications. It is puzzling, however, that the photocurrent is yielded so efficiently in these structures, despite the apparent momentum mismatch between the intralayer/interlayer excitons during the charge transfer, as well as the tightly bound nature of the excitons in 2D geometry. Using the energy-state-resolved ultrafast visible/infrared microspectroscopy, we herein obtain unambiguous experimental evidence of the charge transfer intermediate state with excess energy, during the transition from an intralayer exciton to an interlayer exciton at the interface of a WS 2 /MoS 2 heterostructure, and free carriers moving across the interface much faster than recombining into the intralayer excitons. The observations therefore explain how the remarkable charge transfer rate and photocurrent generation are achieved even with the aforementioned momentum mismatch and excitonic localization in 2D heterostructures and devices.

Original languageEnglish
Article number12512
JournalNature Communications
Volume7
DOIs
Publication statusPublished - 19 Aug 2016
Externally publishedYes

ASJC Scopus subject areas

  • General Chemistry
  • General Biochemistry,Genetics and Molecular Biology
  • General Physics and Astronomy

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