2D Materials and their Application to Near Infrared Detection

Due to their exceptional performance across a wide range of wavelength regions, from UV to broadband detection, 2D materials (2DMs)-based photodetectors have expanded quickly in recent years. 2DMs gained a reputation for playing important roles in photodetection because of their unique physical characteristics, with layer number engineering, low cost and simple preparation, wet chemical processing, deterministic all-dry transfer process, surface passivation for dangle bond-free surface, band gap engineering, valleytronics, and so forth. Given these benefits, the preparation of 2DMs, specifically molybdenum disulfide (MoS2), paves several advantages, and the use of near-infrared detection was the main topic of discussion in this chapter. MoS2 is a well-known transition metal dichalcogenide (TMD) with a tunable bandgap (from ∼1.8 eV in monolayer to ∼1.2 eV in bulk). Heterostructures of MoS2 enable band alignment optimization for extended NIR absorption. Further, the van der Waals heterostructures facilitate efficient charge transfer and reduce recombination losses. In addition, Type-II band alignment in MoS2-based heterostructures promotes carrier separation, enhancing photocurrent generation. Due to these exceptional characters, the proposed chapter covers the fundamentals, operation principles, and fabrication of MoS2 heterostructure-based photodetectors (heterojunction photodetectors), overcoming the generation of dark current, low quantum efficiency, and enhancing detectivity. This chapter offers a thorough guide to achieving high-performance near-infrared photodetectors based on MoS2.