Epitaxial growth of Bi2Se3 topological insulator thin films on Si (111)

In this paper, we report the epitaxial growth of Bi2Se3 thin films on Si (111) substrate, using molecular beam epitaxy (MBE). We show that the as-grown samples have good crystalline quality, and their surfaces exhibit terracelike quintuple layers. Angel-resolved photoemission experiments demonstrate single-Dirac-conelike surface states. These results combined with the temperature- and thickness-dependent magneto-transport measurements, suggest the presence of a shallow impurity band. Below a critical temperature of ∼100K, the surface states of a 7 nm thick film contribute up to 50% of the total conduction.