Monolayer Semiconductor Auger Detector

Colin Ming Earn Chow, Hongyi Yu, John R. Schaibley, Pasqual Rivera, Joseph Finney, Jiaqiang Yan, David Mandrus, Takashi Taniguchi, Kenji Watanabe, Wang Yao, David Henry Cobden, Xiaodong Xu

Research output: Contribution to journalArticlepeer-review

4 Scopus citations

Abstract

Auger recombination in semiconductors is a many-body phenomenon in which the recombination of electrons and holes is accompanied by excitation of other charge carriers. The excess energy of the excited carriers is normally rapidly converted to heat, making Auger processes difficult to probe directly. Here, we employ a technique in which the Auger-excited carriers are detected by their ability to tunnel out of the semiconductor through a thin barrier, generating a current. We use vertical van der Waals heterostructures with monolayer WSe2 as the semiconductor, with hexagonal boron nitride as the tunnel barrier, and a graphite collector electrode. The Auger processes combined with resonant absorption produce characteristic negative photoconductance. We detect holes Auger-excited by both neutral and charged excitons and find that the Auger scattering is surprisingly strong under weak excitation. Our work expands the range of techniques available for probing relaxation processes in 2D materials.

Original languageEnglish (US)
Pages (from-to)5538-5543
Number of pages6
JournalNano Letters
Volume20
Issue number7
DOIs
StatePublished - Jul 8 2020

Keywords

  • Auger photocurrent
  • exciton-hole Auger scattering
  • tunneling barrier
  • van der Waals heterostructure
  • weak excitation

ASJC Scopus subject areas

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

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