The van der Waals epitaxy of Bi2Se3on 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 Bi 2 Se 3 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 Bi 2 Se 3 to proceed. By using vicinal Si(111) substrate surfaces, the in-plane growth rate anisotropy of Bi 2 Se 3 was exploited in order to achieve single crystalline Bi 2 Se 3 epifilms, in which threading defects and twins are effectively suppressed. The optimization of the growth parameters has resulted in the vicinal Bi 2 Se 3 films showing a carrier mobility of ∼2000 cm 2 V −1 s −1 and a background doping of ∼3 × 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.