Fermi-Level Tuning of Epitaxial ${\mathrm{Sb}}_{2}{\mathrm{Te}}_{3}$ Thin Films on Graphene by Regulating Intrinsic Defects and Substrate Transfer Doping

Fermi-Level Tuning of Epitaxial ${Sb}_{2} {Te}_{3}$ Thin Films on Graphene by Regulating Intrinsic Defects and Substrate Transfer Doping

Yeping Jiang, Y. Y. Sun, Mu Chen, Yilin Wang, Zhi Li, Canli Song, Ke He, Lili Wang, Xi Chen, Qi-Kun Xue, Xucun Ma, and S. B. Zhang

Phys. Rev. Lett. 108, 066809 – Published 10 February 2012

Abstract

High-quality ${Sb}_{2} {Te}_{3}$ films are obtained by molecular beam epitaxy on a graphene substrate and investigated by in situ scanning tunneling microscopy and spectroscopy. Intrinsic defects responsible for the natural $p$ -type conductivity of ${Sb}_{2} {Te}_{3}$ are identified to be the Sb vacancies and ${Sb}_{Te}$ antisites in agreement with first-principles calculations. By minimizing defect densities, coupled with a transfer doping by the graphene substrate, the Fermi level of ${Sb}_{2} {Te}_{3}$ thin films can be tuned over the entire range of the bulk band gap. This establishes the necessary condition to explore topological insulator behaviors near the Dirac point.

Received 22 August 2011

DOI:https://doi.org/10.1103/PhysRevLett.108.066809

Authors & Affiliations

Yeping Jiang^1,2, Y. Y. Sun³, Mu Chen^1,2, Yilin Wang¹, Zhi Li¹, Canli Song^1,2, Ke He¹, Lili Wang¹, Xi Chen², Qi-Kun Xue^1,2, Xucun Ma^1,*, and S. B. Zhang^3,†

¹Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
²State Key Lab of Low-Dimensional Physics, Department of Physics, Tsinghua University, Beijing 100084, China
³Department of Physics, Applied Physics, and Astronomy, Rensselaer Polytechnic Institute, Troy, New York 12180, USA