Band structure engineered tunneling heterostructures for high-performance visible and near-infrared photodetection

Tunneling heterostructures are emerging as a versatile architecture for photodetection due to their advanced optical sensitivity, tailorable detection band, and well-balanced photoelectric performances. However, the existing tunneling heterostructures are mainly operated in the visible wavelengths and have been rarely investigated for the near-infrared detection. Herein, we report the design and realization of a novel broken-gap tunneling heterostructure by combining WSe(2)and Bi2Se3, which is able to realize the simultaneous visible and near-infrared detection because of the complementary bandgaps of WSe(2)and Bi2Se3(1.46 and 0.3 eV, respectively). Thanks to the realigned band structure, the heterostructure shows an ultralow dark current below picoampere and a high tunneling-dominated photocurrent. The photodetector based on our tunneling heterostructure exhibits a superior specific detectivity of 7.9x10(12)Jones for a visible incident of 532 nm and 2.2x10(10)Jones for a 1456 nm near-infrared illumination. Our study demonstrates a new band structure engineering avenue for the construction of van der Waals tunneling heterostructures for high-performance wide band photodetection.