Band alignment determination of bulk h-BN and graphene/h-BN laminates using photoelectron emission microscopy

Shuichi Ogawa, Takatoshi Yamada, Ryo Kadowaki, Takashi Taniguchi, Tadashi Abukawa, Yuji Takakuwa

研究成果: Article査読

5 被引用数 (Scopus)

抄録

Because graphene stacked on hexagonal boron nitride (h-BN) exhibits high electron mobility, it is expected to be applied to next-generation high-speed transistors and electron emitters. To further improve the performance of graphene/h-BN devices, it is necessary to determine the band alignment of graphene/h-BN laminates. However, because mechanically peeled h-BN single crystals transferred onto Si substrates are small, pinpoint observation of h-BN with ordinary photoelectron spectroscopy is difficult. In this study, the electric structure of a graphene/h-BN laminate was identified by photoemission electron microscopy and local measurements of valence band and secondary electron spectra using micro-ultraviolet photoelectron spectroscopy were performed. From these measurements, we determined the band alignment of a graphene/h-BN laminate with a crystal size of a few tens of micrometers. The work function and electron affinity measured by photoelectron spectroscopy of single-crystal h-BN were 4.6 and −0.5 eV, respectively. Laminating graphene on h-BN caused the Fermi level of h-BN to rise 0.85 eV above that of nonlaminated h-BN. In addition, it was found that graphene on h-BN displayed weak n-type conductivity. The results obtained in this research are expected to be widely applied in the field of electronics such as electron emitters using h-BN with negative electron affinity.

本文言語English
論文番号144303
ジャーナルJournal of Applied Physics
125
14
DOI
出版ステータスPublished - 2019 4 14

ASJC Scopus subject areas

  • Physics and Astronomy(all)

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