Electrical transport properties and morphology of topological insulator Bi2Se3 thin films with different thickness prepared by magnetron sputtering

Topological insulator Bi2Se3 thin films were grown by magnetron sputtering on Si (1 0 0) substrate and their phase structures and electrical properties were studied. The films have good crystalline quality, and their surfaces exhibited terrace-like quintuple layers. In the high temperature region, contribution from surface carrier and bulk conduction band electrons excited from an impurity band; in the low temperature region, surface electron became dominant. The weak antilocalization (WAL) cusp was observed in the magneto-transport measurement at low temperature under low magnetic field. The linear magnetoresistance (MR) under high-field was found, which was associated with the gapless topological surface states and of quantum origin. Insulating tendency was much stronger in thinner films. The WAL effect became weaker in thicker films. The top surface was only partially decoupled.