Carrier multiplication in van der Waals layered transition metal dichalcogenides

Ji Hee Kim, Matthew R. Bergren, Jin Cheol Park, Subash Adhikari, Michael Lorke, Thomas Frauenheim, Duk Hyun Choe, Beom Kim, Hyunyong Choi, Tom Gregorkiewicz, Young Hee Lee

Research output: Contribution to journalArticlepeer-review

23 Citations (Scopus)


Carrier multiplication (CM) is a process in which high-energy free carriers relax by generation of additional electron-hole pairs rather than by heat dissipation. CM is promising disruptive improvements in photovoltaic energy conversion and light detection technologies. Current state-of-the-art nanomaterials including quantum dots and carbon nanotubes have demonstrated CM, but are not satisfactory owing to high-energy-loss and inherent difficulties with carrier extraction. Here, we report CM in van der Waals (vdW) MoTe2 and WSe2 films, and find characteristics, commencing close to the energy conservation limit and reaching up to 99% CM conversion efficiency with the standard model. This is demonstrated by ultrafast optical spectroscopy with independent approaches, photo-induced absorption, photo-induced bleach, and carrier population dynamics. Combined with a high lateral conductivity and an optimal bandgap below 1 eV, these superior CM characteristics identify vdW materials as an attractive candidate material for highly efficient and mechanically flexible solar cells in the future.

Original languageEnglish
Article number5488
JournalNature communications
Issue number1
Publication statusPublished - 2019 Dec 1

Bibliographical note

Funding Information:
This work was supported by the Institute for Basic Science (IBS-R011-D1).

Publisher Copyright:
© 2019, The Author(s).

All Science Journal Classification (ASJC) codes

  • Chemistry(all)
  • Biochemistry, Genetics and Molecular Biology(all)
  • Physics and Astronomy(all)


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