title: Direct observation of the layer-dependent electronic structure in phosphorene.
abstract: Phosphorene, a single atomic layer of black phosphorus, has recently emerged as a new two-dimensional (2D) material that holds promise for electronic and photonic technologies. Here we experimentally demonstrate that the electronic structure of few-layer phosphorene varies significantly with the number of layers, in good agreement with theoretical predictions. The interband optical transitions cover a wide, technologically important spectral range from the visible to the mid-infrared. In addition, we observe strong photoluminescence in few-layer phosphorene at energies that closely match the absorption edge, indicating that they are direct bandgap semiconductors. The strongly layer-dependent electronic structure of phosphorene, in combination with its high electrical mobility, gives it distinct advantages over other 2D materials in electronic and opto-electronic applications.
authors.affiliation: State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433, China.|Collaborative Innovation Center of Advanced Microstructures, Nanjing 210093, China.
authors.forename: Likai
authors.identifier: 0000-0003-2907-8939
authors.initials: L
authors.lastname: Li
authors.affiliation: Department of Physics, University of California at Berkeley, Berkeley, California 94720, USA.
authors.forename: Jonghwan
authors.initials: J
authors.lastname: Kim
authors.affiliation: Department of Physics, University of California at Berkeley, Berkeley, California 94720, USA.
authors.forename: Chenhao
authors.initials: C
authors.lastname: Jin
authors.affiliation: Collaborative Innovation Center of Advanced Microstructures, Nanjing 210093, China.|Hefei National Laboratory for Physical Science at Microscale and Department of Physics, University of Science and Technology of China, Hefei, Anhui 230026, China.|Key Laboratory of Strongly Coupled Quantum Matter Physics, University of Science and Technology of China, Hefei, Anhui 230026, China.
authors.forename: Guo Jun
authors.initials: GJ
authors.lastname: Ye
authors.affiliation: Department of Physics, University of California at Berkeley, Berkeley, California 94720, USA.|Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
authors.forename: Diana Y
authors.initials: DY
authors.lastname: Qiu
authors.affiliation: Department of Physics, University of California at Berkeley, Berkeley, California 94720, USA.|Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
authors.forename: Felipe H
authors.initials: FH
authors.lastname: da Jornada
authors.affiliation: Department of Physics, University of California at Berkeley, Berkeley, California 94720, USA.
authors.forename: Zhiwen
authors.initials: Z
authors.lastname: Shi
authors.affiliation: Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China.
authors.forename: Long
authors.initials: L
authors.lastname: Chen
authors.affiliation: State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433, China.|Collaborative Innovation Center of Advanced Microstructures, Nanjing 210093, China.
authors.forename: Zuocheng
authors.initials: Z
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433, China.|Collaborative Innovation Center of Advanced Microstructures, Nanjing 210093, China.
authors.forename: Fangyuan
authors.initials: F
authors.lastname: Yang
authors.affiliation: Advanced Materials Laboratory, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan.
authors.forename: Kenji
authors.identifier: 0000-0003-3701-8119
authors.initials: K
authors.lastname: Watanabe
authors.affiliation: Advanced Materials Laboratory, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Taniguchi
authors.affiliation: Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China.
authors.forename: Wencai
authors.initials: W
authors.lastname: Ren
authors.affiliation: Department of Physics, University of California at Berkeley, Berkeley, California 94720, USA.|Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
authors.forename: Steven G
authors.initials: SG
authors.lastname: Louie
authors.affiliation: Collaborative Innovation Center of Advanced Microstructures, Nanjing 210093, China.|Hefei National Laboratory for Physical Science at Microscale and Department of Physics, University of Science and Technology of China, Hefei, Anhui 230026, China.|Key Laboratory of Strongly Coupled Quantum Matter Physics, University of Science and Technology of China, Hefei, Anhui 230026, China.
authors.forename: Xian Hui
authors.initials: XH
authors.lastname: Chen
authors.affiliation: State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433, China.|Collaborative Innovation Center of Advanced Microstructures, Nanjing 210093, China.
authors.forename: Yuanbo
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Department of Physics, University of California at Berkeley, Berkeley, California 94720, USA.|Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.|Berkeley and the Lawrence Berkeley National Laboratory, Kavli Energy NanoSciences Institute at the University of California, Berkeley, California 94720, USA.
authors.forename: Feng
authors.initials: F
authors.lastname: Wang