Highly Efficient and Anomalous Charge Transfer in van der Waals Trilayer Semiconductors

Frank Ceballos, Ming Gang Ju, Samuel D. Lane, Xiao Cheng Zeng, Hui Zhao

Research output: Contribution to journalArticle

34 Scopus citations

Abstract

Two-dimensional materials, such as graphene and monolayer transition metal dichalcogenides, allow the fabrication of multilayer structures without lattice matching restriction. A central issue in developing such artificial materials is to understand and control the interlayer electron transfer process, which plays a key role in harnessing their emergent properties. Recent photoluminescence and transient absorption measurements revealed that the electron transfer in heterobilayers occurs on ultrafast time scales. However, there is still a lack of fundamental understanding on how this process can be so efficient at van der Waals interfaces. Here we show evidence suggesting the coherent nature of such interlayer electron transfer. In a trilayer of MoS2-WS2-MoSe2, electrons excited in MoSe2 transfer to MoS2 in about one picosecond. Surprisingly, these electrons do not populate the middle WS2 layer during this process. Calculations showed the coherent nature of the charge transfer and reproduced the measured electron transfer time. The hole transfer from MoS2 to MoSe2 is also found to be efficient and ultrafast. The separation of electrons and holes extends their lifetimes to more than one nanosecond, suggesting potential applications of such multilayer structures in optoelectronics.

Original languageEnglish (US)
Pages (from-to)1623-1628
Number of pages6
JournalNano Letters
Volume17
Issue number3
DOIs
StatePublished - Mar 8 2017

Keywords

  • charge transfer
  • coherent transport
  • transient absorption
  • transition metal dichalcogenide
  • two-dimensional material
  • van der Waals interface

ASJC Scopus subject areas

  • Bioengineering
  • Chemistry(all)
  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanical Engineering

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