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 WSe2 and Bi2Se3, which is able to realize the simultaneous visible and near-infrared detection because of the complementary bandgaps of WSe2 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 7.9×1012 Jones for a visible incident of 532 nm and 2.2×1010 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.