Unusually efficient photocurrent extraction in monolayer van der Waals heterostructure by tunnelling through discretized barriers

Woo Jong Yu, Quoc An Vu, Hyemin Oh, Hong Gi Nam, Hailong Zhou, Soonyoung Cha, Joo Youn Kim, Alexandra Carvalho, Munseok Jeong, Hyunyong Choi, A. H. Castro Neto, Young Hee Lee, Xiangfeng Duan

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63 Citations (Scopus)

Abstract

Two-dimensional layered transition-metal dichalcogenides have attracted considerable interest for their unique layer-number-dependent properties. In particular, vertical integration of these two-dimensional crystals to form van der Waals heterostructures can open up a new dimension for the design of functional electronic and optoelectronic devices. Here we report the layer-number-dependent photocurrent generation in graphene/MoS 2 /graphene heterostructures by creating a device with two distinct regions containing one-layer and seven-layer MoS 2 to exclude other extrinsic factors. Photoresponse studies reveal that photoresponsivity in one-layer MoS 2 is surprisingly higher than that in seven-layer MoS 2 by seven times. Spectral-dependent studies further show that the internal quantum efficiency in one-layer MoS 2 can reach a maximum of 65%, far higher than the 7% in seven-layer MoS 2. Our theoretical modelling shows that asymmetric potential barriers in the top and bottom interfaces of the graphene/one-layer MoS 2 /graphene heterojunction enable asymmetric carrier tunnelling, to generate usually high photoresponsivity in one-layer MoS 2 device.

Original languageEnglish
Article number13278
JournalNature communications
Volume7
DOIs
Publication statusPublished - 2016 Nov 9

All Science Journal Classification (ASJC) codes

  • Chemistry(all)
  • Biochemistry, Genetics and Molecular Biology(all)
  • Physics and Astronomy(all)

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    Yu, W. J., Vu, Q. A., Oh, H., Nam, H. G., Zhou, H., Cha, S., Kim, J. Y., Carvalho, A., Jeong, M., Choi, H., Castro Neto, A. H., Lee, Y. H., & Duan, X. (2016). Unusually efficient photocurrent extraction in monolayer van der Waals heterostructure by tunnelling through discretized barriers. Nature communications, 7, [13278]. https://doi.org/10.1038/ncomms13278