Fermi level shift in topological insulator–silicon heterostructures

Ultrathin high-quality Bi2Te3 and Bi2Se3 topological insulator nanoplates are prepared on n-type and p-type silicon (111) substrates via vapor phase deposition method forming topological insulator–silicon heterostructures. The quantitative results obtained by Kelvin probe force microscopy indicate that the work function and Fermi level of both Bi2Te3 and Bi2Se3 nanoplates depend on the substrates, which are ascribed to the charge exchange that exists at the interface between nanoplates and silicon substrates with different doping. Our results provide an effective strategy to tune electronic properties of TI nanostructures through topological insulator–silicon heterostructures.

► Bi2Te3 and Bi2Se3 nanoplates are prepared on silicon forming heterostructures.
► Fermi level shift of nanoplates have been determined by Kelvin probe force microscopy.
► The shift is likely caused by the charge exchange at the interface of heterostructures.