Transition from weak antilocalization to linear magnetoresistance by tuning structure geometry and chemical potential in nanostructured Bi2Se3 films.

We report the electrical and magnetic transport behavior in vertical Cu-doped Bi 2 Se 3 nanoplate films prepared by the chemical vapor deposition method. In vertical Cu-doped Bi 2 Se 3 nanoplate films, the topological surface states are tuned by both the large surface-to-bulk ratio and the Cu doping. Due to their high specific surface area, the magnetoresistance of the vertical undoped Bi 2 Se 3 nanoplate film exhibits a weak antilocalization effect, and it indicates that the topological surface state properties are greatly enhanced. In vertical Cu-doped Bi 2 Se 3 nanoplate films, the electron doping is inhibited, and the carrier type is changed from n-type to p-type. The observed linear magnetoresistance is attributed to have a quantum origin from the topological surface states. When the Cu concentration reaches 1.73 at.% in vertical Bi 2 Se 3 nanoplate film, the linear magnetoresistance can be maintained up to 100 K. Meanwhile, these vertical nanoplate films exhibit the 3D magnetotransport property. Thus, using the same material system with a broad range of carrier density and type, our work shows the transition from a weak-antilocalization to linear magnetoresistance in nanostructured topological insulator Bi 2 Se 3 films with an unusual morphology where the nanoplates are vertically aligned to increase the surface area. [Display omitted] • The magnetoresistance exhibits a WAL characteristic in our film with high specific surface area. • The linear magnetoresistance characteristic can be maintained up to 100 K at most. • The carrier type is changed from n-type to p-type in vertical Cu-doped Bi 2 Se 3 nanoplate films. • The TSSs are enhanced greatly by both the large surface-to-bulk ratio and the Cu doping. [ABSTRACT FROM AUTHOR]