Topological insulator Bi2Se3 thin films grown on double-layer graphene by molecular beam epitaxy
Abstract
Atomically flat thin films of topological insulator Bi2Se3 have been grown on double-layer graphene formed on 6H-SiC(0001) substrate by molecular beam epitaxy. By a combined study of reflection high energy electron diffraction and scanning tunneling microscopy, we identified the Se-rich condition and temperature criterion for layer-by-layer growth of epitaxial Bi2Se3 films. The as-grown films without doping exhibit a low defect density of 1.0 0.2x1011/cm2, and become a bulk insulator at a thickness of 10 quintuple layers, as revealed by in situ angle resolved photoemission spectroscopy measurement.
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