Gate-tunable electronic transport in topological insulator Bi$_{2}$Te$_{3}$ thin films synthesized by metal-organic chemical vapor deposition

ORAL

Abstract

Topological insulator is a new state of matter with a nominally insulating gap in the bulk and non-trivial metallic states on the surface. One of the proto-type topological insulator materials, Bi$_{2}$Te$_{3}$, can be synthesized in the form of high quality, wafer scale thin films by metal-organic chemical vapor deposition (MOCVD). Here we present an experimental study of Bi$_{2}$Te$_{3}$ thin films with thickness ranging from a few nm's to 1 $\mu $m synthesized by MOCVD on semi-insulating GaAs (001) substrates. Hall bar shaped devices using atomic layer deposition (ALD) high-k Al$_{2}$O$_{3}$ or HfO$_{2}$ as gate dielectric have been fabricated. We have measured the magneto-transport (including both R$_{xx}$, 4-terminal longitudinal resistance, and R$_{xy}$, the Hall resistance) at various temperatures and gate voltages to probe the possible transport signatures of the topological surface states. We have also studied gate-tunable weak anti-localization in R$_{xx}$(B) for ultra-thin films.

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Authors

  • Helin Cao

    • Physics department, Birck Nanotechnology Center, Purdue University, West Lafayette, IN 47907

  • Rama Venkatasubramanian

    • Center for Solid State Energetics, RTI International, Research Triangle Park, NC 27709

  • Jonathan Pierce

    • Center for Solid State Energetics, RTI International, Research Triangle Park, NC 27709

  • Tai-Lung Wu

    • Physics department, Birck Nanotechnology Center, Purdue University, West Lafayette, IN 47907
    • Department of Physics and Birck Nanotechnology Center, Purdue University, West Lafayette, IN 47907

  • Jifa Tian

    • Department of Physics and Birck Nanotechnology Center, Purdue University, West Lafayette, IN, 47907
    • Physics department, Birck Nanotechnology Center, Purdue University, West Lafayette, IN 47907

  • Isaac Childres

    • Physics department, Birck Nanotechnology Center, Purdue University, West Lafayette, IN 47907
    • Purdue University

  • Yong Chen

    • Purdue University
    • Physics department, Birck Nanotechnology Center, School of Electrical and Computer Engineering, Purdue University, West Lafayette, IN 47907
    • Department of Physics and Birck Nanotechnology Center, Purdue University, West Lafayette, IN 47907
    • Department of Physics, Purdue University