title: Visualizing topological insulating Bi2Te3 quintuple layers on SiO2-capped Si substrates and its contrast optimization.
abstract: Thin Bi2Te3 flakes, with as few as 3 quintuple layers, are optically visualized on the SiO2-capped Si substrates. Their optical contrasts vary with the illumination wavelength, flake thickness and capping layers. The maximum contrast appears at the optimized light with the 570 nm wavelength. The contrast turns reversed when the flake is reduced to less than 20 quintuple layers. A calculation based on the Fresnel law describes the above observation with the constructions of the layer number-wave length-contrast three-dimensional (3D) diagram and the cap thickness-wavelength-contrast 3D diagram, applicative in the current studies of topological insulating flakes.
authors: Department of Physics and National Lab of Solid State Microstructures, Nanjing University, 210093, Nanjing, P. R. China.
authors: Zhaoguo
authors: Z
authors: Li
authors: Yuyuan
authors: Y
authors: Qin
authors: Yuewen
authors: Y
authors: Mu
authors: Taishi
authors: T
authors: Chen
authors: Changhui
authors: C
authors: Xu
authors: Longbing
authors: L
authors: He
authors: Jianguo
authors: J
authors: Wan
authors: Fengqi
authors: F
authors: Song
authors: Jianfeng
authors: J
authors: Zhou
authors: Min
authors: M
authors: Han
authors: Guanghou
authors: G
authors: Wang