Epitaxial synthesis of highly oriented 2D Janus rashba semiconductor BiTeCl and BiTeBr layers

Debarati Hajra, Renee Sailus, Mark Blei, Kentaro Yumigeta, Yuxia Shen, Sefaattin Tongay

Research output: Contribution to journalArticlepeer-review

18 Scopus citations


The family of layered BiTeX (X = Cl, Br, I) compounds are intrinsic Janus semiconductors with giant Rashba-splitting and many exotic surface and bulk physical properties. To date, studies on these materials required mechanical exfoliation from bulk crystals which yielded thick sheets in nonscalable sizes. Here, we report epitaxial synthesis of Janus BiTeCl and BiTeBr sheets through a nanoconversion technique that can produce few triple layers of Rashba semiconductors (<10 nm) on sapphire substrates. The process starts with van der Waals epitaxy of Bi2Te3 sheets on sapphire and converts these sheets to BiTeCl or BiTeBr layers at high temperatures in the presence of chemically reactive BiCl3/BiBr3 inorganic vapor. Systematic Raman, XRD, SEM, EDX, and other studies show that highly crystalline BiTeCl and BiTeBr sheets can be produced on demand. Atomic level growth mechanism is also proposed and discussed to offer further insights into growth process steps. Overall, this work marks the direct deposition of 2D Janus Rashba materials and offers pathways to synthesize other Janus compounds belonging to MXY family members.

Original languageEnglish (US)
Pages (from-to)15626-15632
Number of pages7
JournalACS nano
Issue number11
StatePublished - Nov 24 2020


  • Bismuth tellurohalide
  • Epitaxy
  • Inversion-symmetry
  • Janus
  • Raman spectroscopy
  • Van der Waals gap

ASJC Scopus subject areas

  • Materials Science(all)
  • Engineering(all)
  • Physics and Astronomy(all)


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