Photogating WS2 Photodetectors Using Embedded WSe2 Charge Puddles

Tsung Han Tsai, Zheng Yong Liang, Yung Chang Lin, Cheng Chieh Wang, Kuang I. Lin, Kazu Suenaga, Po Wen Chiu

研究成果: Article同行評審

45 引文 斯高帕斯(Scopus)

摘要

Performance of 2D photodetectors is often predominated by charge traps that offer an effective photogating effect. The device features an ultrahigh gain and responsivity, but at the cost of a retarded temporal response due to the nature of long-lived trap states. In this work, we devise a gain mechanism that originates from massive charge puddles formed in the type-II 2D lateral heterostructures. This concept is demonstrated using graphene-contacted WS2 photodetectors embedded with WSe2 nanodots. Upon light illumination, photoexcited carriers are separated by the built-in field at the WSe2/WS2 heterojunctions (HJs), with holes trapped in the WSe2 nanodots. The resulting WSe2 hole puddles provide a photoconductive gain, as electrons are recirculating during the lifetime of holes that remain trapped in the puddles. The WSe2/WS2 HJ photodetectors exhibit a responsivity of 3 × 102 A/W with a gain of 7 × 102 electrons per photon. Meanwhile, the zero-gate response time is reduced by 5 orders of magnitude as compared to the prior reports for the graphene-contacted pristine WS2 monolayer and WS2/MoS2 heterobilayer photodetectors due to the ultrafast intralayer excitonic dynamics in the WSe2/WS2 HJs.

原文English
頁(從 - 到)4559-4566
頁數8
期刊ACS nano
14
發行號4
DOIs
出版狀態Published - 2020 4月 28

All Science Journal Classification (ASJC) codes

  • 材料科學(全部)
  • 工程 (全部)
  • 物理與天文學 (全部)

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