High mobility, large linear magnetoresistance, and quantum transport phenomena in Bi2Te3 films grown by metallo-organic chemical vapor deposition (MOCVD)

Abstract

We investigated the magnetotransport properties of Bi₂Te₃ films grown on GaAs (001) substrate by a cost-effective metallo-organic chemical vapor deposition (MOCVD). We observed the remarkably high carrier mobility and the giant linear magnetoresistance (carrier mobility ∼ 22 000 cm² V⁻¹ s⁻¹, magnetoresistance ∼ 750% at 1.8 K and 9 T for a 100 nm thick film) that depends on the film thickness. In addition, the Shubnikov–de Haas oscillation was observed, from which the effective mass was calculated to be consistent with the known value. From the thickness dependence of the Shubnikov–de Haas oscillation, it was found that a two dimensional electron gas with the conventional electron nature coexists with the topological Dirac fermion states and dominates the carrier transport in the Bi₂Te₃ film with thickness higher than 300 nm. These results are attributed to the intrinsic nature of Bi₂Te₃ in the high-mobility transport regime obtained by a deliberate choice of the substrate and the growth conditions.