Schottky-Contacted WSe2 Hot-Electron Photodetectors with Fast Response and High Sensitivity

Utilizing the short lifetime of hot electrons, ultrasensitive hotelectron 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 photo-induced carriers for fast transient recovery. The hot-electron photodetectors demonstrated a high rectification ratio of 10(7) and an extremely low dark current of 1 pA/mu m with a high I-light/I-dark ratio of 1.8 x 10(6). Moreover, a high responsivity of 3.69 A/W and detectivity of 2.39 x 10(13) Jones at an incident light power of 5.0 mu W/cm(2) are simultaneously achieved. The present strategy offers an alternative route for ultrasensitive photodetectors with fast response.