Layer-Dependent Electronic and Optical Properties of 2D Black Phosphorus: Fundamentals and Engineering

In 2D materials, the quantum confinement and van der Waals-type interlayer interactions largely govern the fundamental electronic and optical properties, and the dielectric screening plays a dominant role in the excitonic properties. This suggests strongly layer-dependent properties and a central topic is to characterize and control the interlayer interactions in 2D materials and heterostructures. Black phosphorus is an emerging 2D semiconductor with unusually strong interlayer interactions and widely tunable direct bandgaps from the monolayer to the bulk, offering an ideal platform to probe the layer-dependent properties and the crossover from 2D to 3D (i.e., the scaling effects). In this review, a comprehensive and thorough summary of the fundamental physical properties of black phosphorus is presented, with a special focus on the layer-dependence character, including the electronic band structures, optical absorption and photoluminescence, and excitonic properties, as well as the band structure engineering by means of electrical gating, strain, and electrochemical intercalation. Finally, an outlook is given for the future research.

Automated summary

Black phosphorus, an emerging 2D semiconductor with strong interlayer interactions and tunable bandgaps, provides an ideal platform for investigating layer-dependent properties and the transition from 2D to 3D. This review comprehensively summarizes the fundamental physical properties of black phosphorus, emphasizing layer-dependence, and explores band structure engineering through various methods. The outlook for future research is also discussed.