Dynamic Band‐Alignment Modulation in MoTe2/SnSe2 Heterostructure for High Performance Photodetector

Abstract For two‐dimensional (2D) layered material heterojunctions, dynamic modulation of band alignments allows for the design of devices with flexible multi‐functional applications. In this paper, a device structure is presented based on a MoTe 2 /SnSe 2 field‐effect transistor. By applying a bias voltage to the electrostatic gate, the gate voltage is adjusted from negative to positive, causing the heterojunction to transition from type‐III band alignment to type‐II band alignment. The working mechanism and device performance of the heterojunctions with different band alignments are investigated. The device exhibited outstanding detection range (from ultraviolet to infrared), detectivity (2.42 × 10 9 Jones), and speed (1.3 ms). Under a positive gate voltage, a higher ratio of light current to dark current (2×10 3 ) is achieved. To further demonstrate the potential of the high‐performance devices, their reliability is confirmed through their performance in image recognition using deep learning.