AIP Advances (Aug 2015)

Low contact resistance in epitaxial graphene devices for quantum metrology

  • Tom Yager,
  • Arseniy Lartsev,
  • Karin Cedergren,
  • Rositsa Yakimova,
  • Vishal Panchal,
  • Olga Kazakova,
  • Alexander Tzalenchuk,
  • Kyung Ho Kim,
  • Yung Woo Park,
  • Samuel Lara-Avila,
  • Sergey Kubatkin

DOI
https://doi.org/10.1063/1.4928653
Journal volume & issue
Vol. 5, no. 8
pp. 087134 – 087134-7

Abstract

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We investigate Ti/Au contacts to monolayer epitaxial graphene on SiC (0001) for applications in quantum resistance metrology. Using three-terminal measurements in the quantum Hall regime we observed variations in contact resistances ranging from a minimal value of 0.6 Ω up to 11 kΩ. We identify a major source of high-resistance contacts to be due bilayer graphene interruptions to the quantum Hall current, whilst discarding the effects of interface cleanliness and contact geometry for our fabricated devices. Moreover, we experimentally demonstrate methods to improve the reproducibility of low resistance contacts (<10 Ω) suitable for high precision quantum resistance metrology.