响应度
光电探测器
异质结
三极管
光电子学
材料科学
光电导性
电子
纳米点
载流子
石墨烯
超短脉冲
凝聚态物理
物理
纳米技术
光学
激光器
量子点
量子力学
作者
Tsung‐Han Tsai,Zheng-Yong Liang,Yung‐Chang Lin,Cheng-Chieh Wang,Kuang‐I Lin,Kazu Suenaga,Po‐Wen Chiu
出处
期刊:ACS Nano
[American Chemical Society]
日期:2020-04-09
卷期号:14 (4): 4559-4566
被引量:95
标识
DOI:10.1021/acsnano.0c00098
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.
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