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