van der Waals Complementary Barrier Infrared Detector

Abstract

Infrared photodetectors have garnered significant attention in modern optoelectronics due to various applications. However, uncooled infrared photodetectors based on narrow-bandgap materials suffer from high dark current arising from thermal carrier excitation, posing a major challenge in achieving state-of-the-art infrared photodetectors with a blackbody response. In this work, we propose a van der Waals (vdW) complementary barrier infrared detector (CBD), which is composed of an electron barrier from gold/black phosphorus (Au/BP) Schottky contact and a hole barrier from molybdenum disulfide (MoS₂). The device effectively suppresses the diffusion dark current, achieving a low dark current of 0.1 μA at −0.1 V. Furthermore, the device demonstrates excellent infrared response with gate-tunable characteristics, exhibiting a peak detectivity of 8.37 × 10⁹ cm Hz^1/2 W^–1 under blackbody radiation at room temperature. Additionally, the CBD shows strong infrared polarization detection with an anisotropy ratio of 13.9 and exhibits sensitive nondispersive infrared (NDIR) gas detection capability, with a detection limit for methane (CH₄) as low as 23.9 ppm. This work provides a promising strategy for the design of room-temperature high-performance vdW infrared photodetectors.