Anisotropic Etching of Hexagonal Boron Nitride and Graphene: Question of Edge Terminations

Yijing Y. Stehle, Xiahan Sang, Raymond R. Unocic, Dmitry Voylov, Roderick K. Jackson, Sergei Smirnov, Ivan Vlassiouk

Research output: Contribution to journalArticlepeer-review

54 Scopus Citations

Abstract

Chemical vapor deposition (CVD) has been established as the most effective way to grow large area two-dimensional materials. Direct study of the etching process can reveal subtleties of this competing with the growth reaction and thus provide the necessary details of the overall growth mechanism. Here we investigate hydrogen-induced etching of hBN and graphene and compare the results with the classical kinetic Wulff construction model. Formation of the anisotropically etched holes in the center of hBN and graphene single crystals was observed along with the changes in the crystals' circumference. We show that the edges of triangular holes in hBN crystals formed at regular etching conditions are parallel to B-terminated zigzags, opposite to the N-terminated zigzag edges of hBN triangular crystals. The morphology of the etched hBN holes is affected by a disbalance of the B/N ratio upon etching and can be shifted toward the anticipated from the Wulff model N-terminated zigzag by etching in a nitrogen buffer gas instead of a typical argon. For graphene, etched hexagonal holes are terminated by zigzag, while the crystal circumference is gradually changing from a pure zigzag to a slanted angle resulting in dodecagons.

Original languageAmerican English
Pages (from-to)7306-7314
Number of pages9
JournalNano Letters
Volume17
Issue number12
DOIs
StatePublished - 13 Dec 2017

Bibliographical note

Publisher Copyright:
© 2017 American Chemical Society.

NREL Publication Number

  • NREL/JA-4A00-70577

Keywords

  • 2D Materials
  • APCVD
  • boron nitride
  • edge termination
  • graphene
  • hBN
  • hydrogen etching

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