  Topological insulator (TI) materials such as Bi2Te3 and Bi2Se3 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 Bi2Te3 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 (SS) with a single Dirac cone have been clearly
revealed in the electronic band structure measured by ARPES, confirming the TI
nature of the MOCVD Bi2Te3 films. Resistivity and Hall effect measurements have
demonstrated relatively high bulk carrier mobility of ~350 cm^2/Vs at 300K and
~7,400 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.
