Few-layer black phosphorus is a newly emerged two-dimensional material. It has many interesting properties such as strong anisotropy and significant layer-dependence of the electronic structures. The bandgap of few-layer black phosphorus is in the infrared frequency range, bridging the gap of other 2D materials: zero bandgap graphene and visible frequency bandgap transition metal dichalcogenides.In this talk, I'll present our systematic infrared spectroscopic studies of few-layer black phosphorus, with layer thickness ranging from 2-15 layers. Each thickness black phosphorus has its characteristic IR spectrum, which can be served as a fingerprint. The layer-dependent exciton binding energies are determined from our high quality samples, which show the importance of quantum confinement and dielectric confinement.In addition, strain effect on few-layer black phosphorus will be discussed as well.
G. Zhang, S. Huang, A. Chaves, C. Song, V. O. Özçelik, T. Low and H. Yan, Infrared fingerprints of few-layer black phosphorus, Nature Communications8, 14071 (2017)
Guowei Zhang, Andrey Chaves, Shenyang Huang, Fanjie Wang, Qiaoxia Xing, Tony Low, Hugen Yan.Determination of layer-dependent exciton binding energies in few-layer black phosphorus, Science Advances 4, eaap9977 (2018)