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

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 ∼ 22000 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.