Progress on Black Phosphorus Photonics

Recent years have witnessed the rapidly growing interests in the rediscovered black phosphorus (BP), an elemental group-V layered material with very high carrier mobility among all semiconducting layered materials. As a layered semiconductor, the bandgap of intrinsic BP varies from ≈0.3 to 2 eV depending on the thickness. This bandgap value can be tuned to below 50 meV by a moderate external electric field. Adsorption doping and external pressure can also effectively modify its bandgap. The largely tunable bandgap of BP makes it a promising material for infrared optics. Moreover, its unique puckered structure leads to the anisotropic in-plane properties, making it ideal for the exploration of exotic physical phenomena and the realization of novel devices. Here, the fundamental optical properties are reviewed and latest developments on BP photonic and optoelectronic devices are discussed.