Magnetotransport phenomena in Bi₂Se₃ thin film topological insulators grown by hybrid physical chemical vapor deposition

Intrinsic defects in Bi₂Se₃ topological insulators tend to produce a high carrier concentration and current leakage through the bulk material. Bi₂Se₃ thin films were grown by hybrid physical chemical vapor deposition on (0001) Al₂O₃ substrates with high Se vapor pressure to reduce the occurrence of Se vacancies as the main type of defect. Consequently, the carrier concentration was reduced to ∼5.75 × 10¹⁸ cm⁻³ comparable to reported carrier concentration in Bi₂Se₃ thin films. Magnetotransport measurements were performed on the films and the data were analyzed for weak anti-localization using the Hikami-Larkin-Nagaoka model. The estimated α and l_ϕ values showed good agreement with the symplectic case of 2-D transport of topological surface states in the quantum diffusion regime. The temperature and angular dependence of magnetoresistance indicate a large contribution of the 2-D surface carriers to overall transport properties of Bi₂Se₃ thin film