The van der Waals epitaxy of Bi2Se3 on the vicinal Si(111) surface: an approach for preparing high-quality thin films of a topological insulator

The epitaxial growth of thin films of the topological insulator Bi2Se3 on nominally flat and vicinal Si(111) substrates was studied. In order to achieve a planar growth front and better quality epifilms, a two-step growth method was adopted for the van der Waals epitaxy of Bi2Se3 to proceed. By using vicinal Si(111) substrate surfaces, the in-plane growth rate anisotropy of Bi2Se3 was exploited in order to achieve single crystalline Bi2Se3 epifilms, in which threading defects and twins are effectively suppressed. The optimization of the growth parameters has resulted in the vicinal Bi2Se3 films showing a carrier mobility of similar to 2000 cm(2) V-1 s(-1) and a background doping of similar to 3 x 10(18) cm(-3) of the as-grown layers. Such samples not only show a relatively high magnetoresistance but also show a linear dependence on the magnetic field.