Fabrication of Topological Insulator Bi2Se3−PbSe Heterojunction Photodetector for Infrared Detection

A van der Waals heterojunction is successfully constructed with topological insulator (TI) Bi 2 Se 3 and traditional narrow‐gap PbSe via molecular beam epitaxy. High‐quality crystallization and an atomically abrupt heterointerface between Bi 2 Se 3 and PbSe are observed in the Bi 2 Se 3 −PbSe heterojunction. Prominent photosensitivity in the infrared band is achieved with the as‐fabricated Bi 2 Se 3 −PbSe photodetector. Under zero bias, responsivity and detectivity are 3.9 A W −1 and 8.7 × 10 11 cm Hz 0.5 W −1 , respectively. With a response time of several milliseconds, fast response speed is also achieved. Prominent photosensitivity and fast response speed together suggest that the construction of TI Bi 2 Se 3 −PbSe heterojunction is a promising solution to fabricate high‐performance infrared photodetector.