Philip Hofmann

Ultrafast Band Structure Control of a Two-Dimensional Heterostructure

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  • Søren Ulstrup
  • Antonija Grubisic Cabo
  • ,
  • Jill Miwa
  • Jonathon M. Riley, University of St. Andrews, Storbritannien
  • Signe Strange Grønborg
  • ,
  • Jens C. Johannsen, EPFL Switzerland, Schweiz
  • Cephise Cacho, Central Laser Facility, STFC Rutherford Appleton Laboratory, Storbritannien
  • Oliver Alexander, Central Laser Facility, STFC Rutherford Appleton Laboratory, Storbritannien
  • Richard T. Chapman, Central Laser Facility, STFC Rutherford Appleton Laboratory, Storbritannien
  • Emma Springate, Central Laser Facility, STFC Rutherford Appleton Laboratory, Storbritannien
  • Marco Bianchi
  • Maciej Dendzik
  • ,
  • Jeppe V. Lauritsen
  • Phil D. C. King, University of St. Andrews, Storbritannien
  • 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.
OriginalsprogEngelsk
TidsskriftA C S Nano
Vol/bind10
Nummer6
Sider (fra-til)6315-6322
ISSN1936-0851
DOI
StatusUdgivet - 6 jun. 2016

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