title: Liquid-gated ambipolar transport in ultrathin films of a topological insulator Bi2Te3.
abstract: Using ionic-liquid (IL) gating in electric-double-layer transistors (EDLTs), we investigate field-effect electrical transport properties of ultrathin epitaxial films of a topological insulator (TI), Bi(2)Te(3). Because of their extreme thinness, the Bi(2)Te(3) films show a band gap opening and resulting semiconducting transport properties. Near room temperature, an obvious ambipolar transistor operation with an ON-OFF ratio close to 10(3) was observed in the transfer characteristics of liquid-gated EDLTs and further confirmed by a sign change of the Hall coefficients. Modulation of the electronic states and a phase transition from a semiconducting conduction (dR(xx)/dT < 0) to a metallic transport (dR(xx)/dT > 0) were observed in the temperature-dependent resistance of the ultrathin Bi(2)Te(3) channel, demonstrating that the liquid gating is an effective way to modulate the electronic states of TIs.
authors.affiliation: Quantum-Phase Electronics Center and Department of Applied Physics, The University of Tokyo, Tokyo, 113-8656, Japan. htyuan@ap.t.u-tokyo.ac.jp
authors.forename: Hongtao
authors.initials: H
authors.lastname: Yuan
authors.forename: Hongwen
authors.initials: H
authors.lastname: Liu
authors.forename: Hidekazu
authors.initials: H
authors.lastname: Shimotani
authors.forename: Hua
authors.initials: H
authors.lastname: Guo
authors.forename: Mingwei
authors.initials: M
authors.lastname: Chen
authors.forename: Qikun
authors.initials: Q
authors.lastname: Xue
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Iwasa
mesh_terms: D001729:Bismuth / Q000737:chemistry*; D052578:Ionic Liquids / Q000737:chemistry*; D008567:Membranes, Artificial; D036103:Nanotechnology; D010316:Particle Size; D013499:Surface Properties; D013691:Tellurium / Q000737:chemistry*; D013696:Temperature; D014173:Transistors, Electronic
chemical_list: D052578:Ionic Liquids; D008567:Membranes, Artificial; C542787:bismuth telluride; D013691:Tellurium; D001729:Bismuth