Liquid-gated ambipolar transport in ultrathin films of a topological insulator Bi2Te3

Hongtao Yuan, Hongwen Liu, Hidekazu Shimotani, Hua Guo, Mingwei Chen, Qikun Xue, Yoshihiro Iwasa

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81 Citations (Scopus)


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), Bi2Te 3. Because of their extreme thinness, the Bi2Te 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 103 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 (dRxx/dT < 0) to a metallic transport (dRxx/dT > 0) were observed in the temperature-dependent resistance of the ultrathin Bi2Te3 channel, demonstrating that the liquid gating is an effective way to modulate the electronic states of TIs.

Original languageEnglish
Pages (from-to)2601-2605
Number of pages5
JournalNano Letters
Issue number7
Publication statusPublished - 2011 Jul 13


  • ambipolar transistor
  • bismuth telluride
  • electronic transport
  • liquid gating
  • Topological insulator


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