Aarhus University Seal / Aarhus Universitets segl

Søren Ulstrup

Ultrafast Band Structure Control of a Two-Dimensional Heterostructure

Research output: Contribution to journal/Conference contribution in journal/Contribution to newspaperJournal articleResearchpeer-review

  • Søren Ulstrup
  • Antonija Grubisic Cabo
  • ,
  • Jill Miwa
  • Jonathon M. Riley, University of St. Andrews, United Kingdom
  • Signe Strange Grønborg
  • ,
  • Jens C. Johannsen, EPFL Switzerland, Switzerland
  • Cephise Cacho, Central Laser Facility, STFC Rutherford Appleton Laboratory, United Kingdom
  • Oliver Alexander, Central Laser Facility, STFC Rutherford Appleton Laboratory, United Kingdom
  • Richard T. Chapman, Central Laser Facility, STFC Rutherford Appleton Laboratory, United Kingdom
  • Emma Springate, Central Laser Facility, STFC Rutherford Appleton Laboratory, United Kingdom
  • Marco Bianchi
  • Maciej Dendzik
  • ,
  • Jeppe V. Lauritsen
  • Phil D. C. King, University of St. Andrews, United Kingdom
  • Philip Hofmann
The electronic structure of two-dimensional (2D) semiconductors can be significantly altered by screening effects, either from free charge carriers in the material or by environmental screening from the surrounding medium. The physical properties of 2D semiconductors placed in a heterostructure with other 2D materials are therefore governed by a complex interplay of both intra- and interlayer interactions. Here, using time- and angle-resolved photo emission, we are able to isolate both the layer-resolved band structure and, more importantly, the transient band structure evolution of a model 2D heterostructure formed of a single layer of MoS2 on graphene. Our results reveal a pronounced renormalization of the quasiparticle gap of the MoS2 layer. Following optical excitation, the band gap is reduced by up to similar to 400 meV on femtosecond time scales due to a persistence of strong electronic interactions despite the environmental screening by the n -doped graphene. This points to a large degree of tunability of both the electronic structure and the electron dynamics for 2D semiconductors embedded in a van der Waals-bonded heterostructure.
Original languageEnglish
JournalA C S Nano
Volume10
Issue6
Pages (from-to)6315-6322
ISSN1936-0851
DOIs
Publication statusPublished - 6 Jun 2016

See relations at Aarhus University Citationformats

ID: 101057578