带结构工程隧穿异质结用于高性能可见和近红外光探测

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

隧穿异质结因其先进的光学灵敏度、可定制的探测范围以及均衡的光电性能而正逐渐成为一种光电探测的通用体系结构.但是,现有的隧穿异质结主要在可见光波段工作,很少能实现近红外光探测.本文利用具有互补带隙的WSe2和Bi2Se3(1.46和0.3 eV)设计了一种能同时实现高性能可见和近红外光探测的新型裂隙隧穿异质结.由于能带结构的重新排列,WSe2/Bi2Se3异质结构展现出了低于pA量级的暗电流和以隧穿为主的光电流.我们设计的隧穿异质结对532 nm可见光和1456 nm近红外光的比探测度高达7.9×1012和2.2×1010Jones.本研究为构建用于高性能宽带光探测的范德瓦尔斯隧穿异质结构提供了一种新的带结构工程途径.

Tunneling heterostructures are emerging as a versatile architecture for photodetection due to their advanced optical sensitivity,tailorable detection band,and wellbalanced photoelectric performances.However,the existing tunneling heterostructures are mainly operated in the visible wavelengths and have been rarely investigated for the nearinfrared 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 e V 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 7.9×1012Jones for a visible incident of 532 nm and 2.2×1010Jones for a 1456 nm nearinfrared 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.