posted on 2021-12-20, 15:04authored byMingliang Zhang, Xingqiang Liu, Xinpei Duan, Sen Zhang, Chang Liu, Da Wan, Guoli Li, Zhen Xia, Zhiyong Fan, Lei Liao
Utilizing
the short lifetime of hot electrons, ultrasensitive hot-electron
photodetectors with fast response speed can be developed that have
the potential to carve a niche among the photoconductive devices.
Herein, high-performance WSe2 photodetectors are fabricated
based on hot-electron transportation, in which an ultrathin Al2O3 layer enables screening of high-energy hot electrons
and promises ultrasensitive response to incident light, and the built-in
electric field in Schottky junctions separates the photoinduced carriers
for fast transient recovery. The hot-electron photodetectors demonstrated
a high rectification ratio of 107 and an extremely low
dark current of 1 pA/μm with a high Ilight/Idark ratio of 1.8 × 106. Moreover, a high responsivity of 3.69 A/W and detectivity of 2.39
× 1013 Jones at an incident light power of 5.0 μW/cm2 are simultaneously achieved. The present strategy offers
an alternative route for ultrasensitive photodetectors with fast response.