Deposition of topological insulator Sb2Te3 films by an MOCVD process
Layered Sb2Te3 films were grown by a MOCVD process on Al2O3(0001) substrates at 400 °C by use of i-Pr3Sb and Et2Te2 and characterized by SEM, AFM, XRD, EDX and Auger spectroscopy. The electrical sheet resistivity was measured in the range of 4 to 400 K, showing a monotonic increase with increasing temperature. The valence band structure probed by angle-resolved photoemission shows the detailed dispersions of the bulk valence band and the topological surface state of a quality no less than for optimized bulk single crystals. The surface state dispersion gives a Dirac point roughly 30 meV above the Fermi level leading to hole doping and the presence of bulk valence states at the Fermi energy.