• 文献标题:   In Situ Study of Hydrogenation of Graphene and New Phases of Localization between Metal-Insulator Transitions
  • 文献类型:   Article
  • 作  者:   JAYASINGHA R, SHEREHIY A, WU SY, SUMANASEKERA GU
  • 作者关键词:   graphene, magnetoresistance, weak localization, strong localization, hydrogenation, metalinsulator transition
  • 出版物名称:   NANO LETTERS
  • ISSN:   1530-6984 EI 1530-6992
  • 通讯作者地址:   Univ Louisville
  • 被引频次:   20
  • DOI:   10.1021/nl402272b
  • 出版年:   2013

▎ 摘  要

Monolayer graphene synthesized by chemical vapor deposition was subjected to controlled and sequential hydrogenation using RF plasma while monitoring its electrical properties in situ. Low-temperature transport properties, namely, electrical resistance (R), thermopower (S), Hall mobility GO, and magnetoresistance (MR), were measured for each sample and correlated with ex situ Raman scattering and X-ray photoemission (XPS) characteristics. For weak hydrogenation, the transport is seen to be governed by electron diffusion, and low-temperature transport properties show metallic behavior (conductance G remains nonzero as T -> 0). For strong hydrogenation, the transport is found to be describable by variable range hopping (VRH) and the low T conductance shows insulating behavior (G -> 0 as T -> 0). Weak localization (WL) behavior is seen with a negative MR for weakly hydrogenated graphene, and these WL effects are seen to diminish as the hydrogenation progresses. A clear transition to strong localization (SL) is evident with the emergence of pronounced negative MR for strongly hydrogenated graphene.