The optical conductivity of few-layer black phosphorus by infrared spectroscopy

Abstract

The strength of light-matter interaction is of central importance in photonics and optoelectronics. For many widely studied two-dimensional semiconductors, such as MoS2, the optical absorption due to exciton resonances increases with thickness. However, here we will show, few-layer black phosphorus exhibits an opposite trend. We determine the optical conductivity of few-layer black phosphorus with thickness down to bilayer by infrared spectroscopy. On the contrary to our expectations, the frequency-integrated exciton absorption is found to be enhanced in thinner samples. Moreover, the continuum absorption near the band edge is almost a constant, independent of the thickness. We will show such scenario is related to the quanta of the universal optical conductivity of graphene, with a prefactor originating from the band anisotropy.

22 pages, 4 figures

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Cited by in corpus (8)

• Tunable intraband optical conductivity and polarization-dependent epsilon-near-zero behavior in black phosphorus
• Prediction of hyperbolic exciton-polaritons in monolayer black phosphorus
• The optical properties of few-layer InSe
• Anisotropic Infrared Response and Orientation-dependent Strain-tuning of the Electronic Structure in Nb2SiTe4
• Layer-dependent exciton polarizability and the brightening of dark excitons in few-layer black phosphorus
• Comparison of Optical Response from DFT Random Phase Approximation and Low-Energy Effective Model: Strained Phosphorene
• Spin-orbit coupling effects in single-layer phosphorene
• Optical conductivity as a probe of the interaction-driven metal in rhombohedral trilayer graphene