• 文献标题:   Restoring the photovoltaic effect in graphene-based van der Waals heterojunctions towards self-powered high-detectivity photodetectors
  • 文献类型:   Article
  • 作  者:   LI H, LI XM, PARK JH, TAO L, KIM KK, LEE YH, XU JB
  • 作者关键词:   photodetector, graphene, photovoltaic, tunneling, specific detectivity
  • 出版物名称:   NANO ENERGY
  • ISSN:   2211-2855 EI 2211-3282
  • 通讯作者地址:   Chinese Univ Hong Kong
  • 被引频次:   17
  • DOI:   10.1016/j.nanoen.2018.12.004
  • 出版年:   2019

▎ 摘  要

Photodiodes composed of graphene and other two-dimensional materials are potential for high-sensitivity self-powered photodetectors, but the photovoltaic effect of graphene-based two-dimensional heterojunctions is often depressed and is, therefore, weaker than what it is expected. In this work, we have revealed that the loss of zero-bias photocurrent in the molybdenum disulfide (MoS2)/graphene photodiode originates from the interlayer coupling of photocarriers at the interface. By introducing atomically thin hexagonal boron nitride (h-BN) film into the MoS2/graphene interface, the interlayer carrier coupling at the MoS2/graphene interface under zero-bias is substantially blocked by the h-BN layer while the transport of photo-generated holes is realized through quantum tunneling. Therefore, the insertion of h-BN could increase the zero-bias photocurrent of the MoS2/graphene heterojunction for over three orders, and a high-sensitivity self-power vertical MoS2/h-BN/graphene van der Waals (vdW) heterostructure tunneling photodetector can be developed, which exhibits a high photo conversion efficiency (external quantum efficiency over 80%), improved photocurrent to dark current ratio (over 1000) and a corresponding high specific detectivity (5.9 x 10(14) Jones for white-noise limited detectivity and 6.7 x 10(10) Jones for the measured detectivity). This intriguing photovoltaic effect restoring has significant potential in practical applications of high-sensitivity graphene-based self-powered photodetection.