Two-dimensional van der Waals high-speed photodetectors enhanced by surface and interface engineering

Surface and interface engineering are effective methods for tailoring the properties of two-dimensional (2D) van der Waals (vdW) materials. These techniques enable fine-tuning of critical factors that dictate photoelectric conversion processes, including but not limited to carrier dynamics, built-in electric fields, and interface coupling strength. This opens up possibilities to unlock the full potential of 2D materials for developing high-speed optoelectronic devices. Such advancements are pivotal for realizing next-generation optical interconnects, which are expected to revolutionize data transmission and optical communication technologies. However, a comprehensive understanding of surface and interface engineering in 2D vdW materials for high-speed photodetection is lacking. This review endeavors to delineate the working mechanisms of these materials and provide an extensive overview of advances in engineered 2D high-speed photodetectors, with emphasis on critical aspects such as vertical channel engineering, band alignment engineering, defect engineering, hot-carrier engineering, contact engineering, and waveguide integration. The review also explores innovative strategies developed to surmount the inherent trade-off between response speed and sensitivity. Furthermore, it highlights the prevailing challenges and prospects in the realm of 2D vdW materials for high-speed photodetection.