title: Layer Identification of Colorful Black Phosphorus.
abstract: A quick method for estimating the layer number of black phosphorus is demonstrated by simple color-comparison using optical microscope in this paper. A thickness-dependent reflection model of black phosphorus/SiO2/Si is constructed and a colorbar confirmed by experiments is obtained for quick identifying layer number. The enhanced visibility affected by substrates or wavelength of light is further verified by calculating the contrast.
authors.affiliation: State Key Laboratory of Mechanics and Control of Mechanical Structures, Key Laboratory for Intelligent Nano Materials and Devices of Ministry of Education and Institute of Nano Science, Nanjing University of Aeronautics and Astronautics, Nanjing, 210016, China.
authors.forename: Hongye
authors.initials: H
authors.lastname: Chen
authors.affiliation: State Key Laboratory of Mechanics and Control of Mechanical Structures, Key Laboratory for Intelligent Nano Materials and Devices of Ministry of Education and Institute of Nano Science, Nanjing University of Aeronautics and Astronautics, Nanjing, 210016, China.
authors.forename: Wenwen
authors.initials: W
authors.lastname: Fei
authors.affiliation: State Key Laboratory of Mechanics and Control of Mechanical Structures, Key Laboratory for Intelligent Nano Materials and Devices of Ministry of Education and Institute of Nano Science, Nanjing University of Aeronautics and Astronautics, Nanjing, 210016, China.
authors.forename: Jianxin
authors.initials: J
authors.lastname: Zhou
authors.affiliation: State Key Laboratory of Mechanics and Control of Mechanical Structures, Key Laboratory for Intelligent Nano Materials and Devices of Ministry of Education and Institute of Nano Science, Nanjing University of Aeronautics and Astronautics, Nanjing, 210016, China.
authors.forename: Chunyang
authors.initials: C
authors.lastname: Miao
authors.affiliation: State Key Laboratory of Mechanics and Control of Mechanical Structures, Key Laboratory for Intelligent Nano Materials and Devices of Ministry of Education and Institute of Nano Science, Nanjing University of Aeronautics and Astronautics, Nanjing, 210016, China.
authors.forename: Wanlin
authors.initials: W
authors.lastname: Guo
keywords: black phosphorus; colors; layer numbers; monochromatic light; optical methods