Two‐Dimensional Materials for Infrared Photodetectors: Material Design, Device Architectures, and Performance Optimization

ABSTRACT Infrared photodetectors (IRPDs) are indispensable in modern technology, with applications spanning thermal imaging, environmental monitoring, and biomedical diagnostics. The performance and applicability of IRPDs depend on the properties of their constituent materials. Two‐dimensional (2D) materials, known for their tunable bandgaps, superior carrier dynamics, and unique optoelectronic properties, are promising candidates for high‐performance photodetection across the near‐infrared (NIR) to mid‐infrared (MIR) spectral ranges. This review elucidates the fundamental principles and key challenges in designing 2D‐material‐based IRPDs, outlining corresponding mitigation strategies. Subsequently, we provide an overview of recent advances in device architectures, including van der Waals (vdWs) heterostructures, tunneling junctions, vertical channels, monopolar potential barriers, and interface engineering. These device architectures are discussed across graphene, black phosphorus (BP), transition metal dichalcogenides (TMDs), MXenes, and other emerging 2D materials, with emphasis on responsivity, specific detectivity, and response speed. Beyond single‐pixel innovations, we highlight the transition toward practical imaging systems, emphasizing arrayed devices, pixel uniformity, wafer‐scale processing, and readout‐integrated circuit (ROIC) integration for focal plane arrays (FPAs). Finally, we summarize the field and offer perspectives on remaining challenges and future research directions toward scalable, high‐performance infrared photodetection based on 2D materials.