Terahertz emission from 2D nanomaterials

Kateryna Kushnir, Mengjing Wang, Ying Qin, Guangjiang Li, Sefaattin Tongay, Kristie J. Koski, Lyubov V. Titova

Research output: Chapter in Book/Report/Conference proceedingConference contribution

3 Scopus citations


Group-IV monochalcogenides belong to a family of 2D layered materials. Monolayers of group-IV monochalcogenides GeS, GeSe, SnS and SnSe have been theoretically predicted to exhibit a large shift current owing to a spontaneous electric polarization at room temperature. Using THz emission spectroscopy, we find that above band gap photoexcitation with ultrashort laser pulses results in emission of nearly single-cycle THz pulses due to a surface shift current in multi-layer, sub-μm to few-μm thick GeS and GeSe, as inversion symmetry breaking at the crystal surface enables THz emission by the shift current. Experimental demonstration of THz emission by the surface shift current puts this layered group-IV monochalcogenides forward as a candidate for next generation shift current photovoltaics, nonlinear photonic devices and THz sources.

Original languageEnglish (US)
Title of host publicationTerahertz Emitters, Receivers, and Applications IX
EditorsManijeh Razeghi, Alexei N. Baranov
ISBN (Electronic)9781510620834
StatePublished - 2018
EventTerahertz Emitters, Receivers, and Applications IX 2018 - San Diego, United States
Duration: Aug 19 2018Aug 20 2018

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
ISSN (Print)0277-786X
ISSN (Electronic)1996-756X


ConferenceTerahertz Emitters, Receivers, and Applications IX 2018
Country/TerritoryUnited States
CitySan Diego


  • 2D materials
  • GeS
  • GeSe
  • Terahertz emission spectroscopy
  • shift current
  • terahertz generation

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering


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