Surface State Transport and Ambipolar Electric Field Effect in Bi2Se3 Nanodevices

Abstract

Electronic transport experiments involving the topologically protected states found at the surface of Bi2Se3 and other topological insulators require fine control over carrier density, which is challenging with existing bulk-doped material. Here we report on electronic transport measurements on thin (<100 nm) Bi2Se3 devices and show that the density of the surface states can be modulated via the electric field effect by using a top-gate with a high-k dielectric insulator. The conductance dependence on geometry, gate voltage, and temperature all indicate that transport is governed by parallel surface and bulk contributions. Moreover, the conductance dependence on top-gate voltage is ambipolar, consistent with tuning between electrons and hole carriers at the surface.

This paper is a significantly revised version of http://arxiv.org/abs/1003.3137, including new title, and therefore submitted as a new arxiv paper

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Cited by in corpus (4)

• Bulk Band Gap and Surface State Conduction Observed in Voltage-Tuned Crystals of the Topological Insulator Bi${}_2$Se${}_3$
• Nonlinear optical probe of tunable surface electrons on a topological insulator
• Surface versus bulk state in topological insulator Bi2Se3 under environmental disorder
• Atomic-Layer-Deposited Al2O3 on Bi2Te3 for Topological Insulator Field-Effect Transistors