Exciton pumping across type-I gallium chalcogenide heterojunctions

Hui Cai, Jun Kang, Hasan Sahin, Bin Chen, Aslihan Suslu, Kedi Wu, Francois Peeters, Xiuqing Meng, Sefaattin Tongay

Research output: Contribution to journalArticle

15 Scopus citations

Abstract

Quasi-two-dimensional gallium chalcogenide heterostructures are created by transferring exfoliated few-layer GaSe onto bulk GaTe sheets. Luminescence spectroscopy measurements reveal that the light emission from underlying GaTe layers drastically increases on heterojunction regions where GaSe layers make contact with the GaTe. Density functional theory (DFT) and band offset calculations show that conduction band minimum (CBM) (valance band maximum (VBM)) values of GaSe are higher (lower) in energy compared to GaTe, forming type-I band alignment at the interface. Consequently, GaSe layers provide photo-excited electrons and holes to GaTe sheets through relatively large built-in potential at the interface, increasing overall exciton population and light emission from GaTe. Observed results are not specific to the GaSe/GaTe system but observed on GaS/GaSe heterolayers with type-I band alignment. Observed experimental findings and theoretical studies provide unique insights into interface effects across dissimilar gallium chalcogenides and offer new ways to boost optical performance by simple epitaxial coating.

Original languageEnglish (US)
Article number065203
JournalNanotechnology
Volume27
Issue number6
DOIs
StatePublished - Jan 13 2016

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Keywords

  • 2D materials
  • atomically thin layers
  • gallium chalcogenides
  • heterojunctions
  • optics

ASJC Scopus subject areas

  • Bioengineering
  • Chemistry(all)
  • Materials Science(all)
  • Mechanics of Materials
  • Mechanical Engineering
  • Electrical and Electronic Engineering

Cite this

Cai, H., Kang, J., Sahin, H., Chen, B., Suslu, A., Wu, K., Peeters, F., Meng, X., & Tongay, S. (2016). Exciton pumping across type-I gallium chalcogenide heterojunctions. Nanotechnology, 27(6), [065203]. https://doi.org/10.1088/0957-4484/27/6/065203