Topological insulator Bi ₂Te ₃ films synthesized by metal organic chemical vapor deposition

Topological insulator (TI) materials such as Bi ₂Te ₃ and Bi ₂Se ₃ have attracted strong recent interests. Large scale, high quality TI thin films are important for developing TI-based device applications. In this work, structural and electronic properties of Bi ₂Te ₃ thin films deposited by metal organic chemical vapor deposition (MOCVD) on GaAs (001) substrates were characterized via x-ray diffraction (XRD), Raman spectroscopy, angle-resolved photoemission spectroscopy (ARPES), and electronic transport measurements. The characteristic topological surface states with a single Dirac cone have been clearly revealed in the electronic band structure measured by ARPES, confirming the TI nature of the MOCVD Bi ₂Te ₃ films. Resistivity and Hall effect measurements have demonstrated relatively high bulk carrier mobility of ∼350 cm ²/Vs at 300 K and ∼7400 cm ²/Vs at 15 K. We have also measured the Seebeck coefficient of the films. Our demonstration of high quality topological insulator films grown by a simple and scalable method is of interests for both fundamental research and practical applications of thermoelectric and TI materials.