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arXiv · 2004.07114

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

Guowei Zhang·Shenyang Huang·Fanjie Wang·Qiaoxia Xing·Chaoyu Song·Chong Wang·Yuchen Lei·Mingyuan Huang·Hugen Yan
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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.

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Guowei Zhang, Shenyang Huang, Fanjie Wang, Qiaoxia Xing, Chaoyu Song, Chong Wang, Yuchen Lei, Mingyuan Huang, Hugen Yan. 2020-04-15. The optical conductivity of few-layer black phosphorus by infrared spectroscopy. https://doi.org/10.1038/s41467-020-15699-7

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