• 文献标题:   Ballistic transport of graphene pnp junctions with embedded local gates
  • 文献类型:   Article
  • 作  者:   NAM SG, KI DK, PARK JW, KIM Y, KIM JS, LEE HJ
  • 作者关键词:  
  • 出版物名称:   NANOTECHNOLOGY
  • ISSN:   0957-4484
  • 通讯作者地址:   Pohang Univ Sci Technol
  • 被引频次:   21
  • DOI:   10.1088/0957-4484/22/41/415203
  • 出版年:   2011

▎ 摘  要

We fabricated graphene pnp devices, by embedding pre-defined local gates in an oxidized surface layer of a silicon substrate. With neither deposition of dielectric material on the graphene nor electron-beam irradiation, we obtained high-quality graphene pnp devices without degradation of the carrier mobility even in the local-gate region. The corresponding increased mean free path leads to the observation of ballistic and phase-coherent transport across a local gate 130 nm wide, which is about an order of magnitude wider than reported previously. Furthermore, in our scheme, we demonstrated independent control of the carrier density in the local-gate region, with a conductance map very much distinct from those of top-gated devices. This was caused by the electric field arising from the global back gate being strongly screened by the embedded local gate. Our scheme allows the realization of ideal multipolar graphene junctions with ballistic carrier transport.