title: Influence of Thickness on the Electrical Transport Properties of Exfoliated Bi2Te3 Ultrathin Films.
abstract: In this work, the mechanical exfoliation method has been utilized to fabricate Bi2Te3 ultrathin films. The thickness of the ultrathin films is revealed to be several tens of nanometers. Weak antilocalization effects and Shubnikov de Haas oscillations have been observed in the magneto-transport measurements on individual films with different thickness, and the two-dimensional surface conduction plays a dominant role. The Fermi level is found to be 81 meV above the Dirac point, and the carrier mobility can reach ~6030 cm(2)/(Vs) for the 10-nm film. When the film thickness decreases from 30 to 10 nm, the Fermi level will move 8 meV far from the bulk valence band. The coefficient α in the Hikami-Larkin-Nagaoka equation is shown to be ~0.5, manifesting that only the bottom surface of the Bi2Te3 ultrathin films takes part in transport conductions. These will pave the way for understanding thoroughly the surface transport properties of topological insulators.
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: D L
authors.initials: DL
authors.lastname: Mo
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: W B
authors.initials: WB
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai, 200433, China. qcai@fudan.edu.cn.|Collaborative Innovation Center of Advanced Microstructures, Nanjing, 210093, China. qcai@fudan.edu.cn.
authors.forename: Q
authors.identifier: http://orcid.org/0000-0001-6724-303X
authors.initials: Q
authors.lastname: Cai
keywords: Bi2Te3 ultrathin films; Exfoliation; Shubnikov de Haas oscillations; Thickness influence; Weak antilocalization