Top gating of epitaxial (Bi_{1-x}Sb_x)2Te3 topological insulator thin films

Abstract

The tunability of the chemical potential for a wide range encompassing the Dirac point is important for many future devices based on topological insulators. Here we report a method to fabricate highly efficient top gates on epitaxially grown (Bi_{1-x}Sb_x)2Te3 topological insulator thin films without degrading the film quality. By combining an in situ deposited Al2O3 capping layer and a SiN_x dielectric layer deposited at low temperature, we were able to protect the films from degradation during the fabrication processes. We demonstrate that by using this top gate, the carriers in the top surface can be efficiently tuned from n- to p-type. We also show that magnetotransport properties give evidence for decoupled transport through top and bottom surfaces for the entire range of gate voltage, which is only possible in truly bulk-insulating samples.

5 pages, 3 figures; accepted for publication in Appl. Phys. Lett

References in corpus (8)

• Ultrahigh electron mobility in suspended graphene
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• Impurity effect on weak anti-localization in the topological insulator Bi2Te3
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• Observation of Dirac Holes and Electrons in a Topological Insulator
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• Weak Localization and Antilocalization in Topological Insulator Thin Films with Coherent Bulk-Surface Coupling
• Atomic-Layer-Deposited Al2O3 on Bi2Te3 for Topological Insulator Field-Effect Transistors

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• Quantum Transport and Potential of Topological States for Thermoelectricity in Bi${}_2$Te${}_3$ Thin Films
• Top-down fabrication of bulk-insulating topological insulator nanowires for quantum devices
• Topological insulator spin transistor
• Electrostatic Modulation of the Electronic Properties of Dirac Semimetal Na3Bi
• Robust Gapless Surface State against Surface Magnetic Impurities on (Bi${}_{0.5}$Sb${}_{0.5}$)${}_2$Te${}_3$ Evidenced by In Situ Magnetotransport Measurements
• Characterizing the chemical potential disorder in the topological insulator (Bi${}_{1-x}$Sb${}_x$)${}_2$Te${}_3$ thin films
• Relaxation dynamics of the optically driven nonequilibrium states in the electron- and hole-doped topological-insulator materials $(B{i}_{1-x}S{b}_x{)}_{2}T{e}_3$
• From classical to quantum regime of topological surface states via defect engineering