Surface structure promoted high-yield growth and magnetotransport properties of Bi₂Se₃ nanoribbons

In the present work, a catalyst-free physical vapour deposition method is used to synthesize high yield of Bi₂Se₃ nanoribbons. By replacing standard glass or quartz substrates with aluminium covered with ultrathin porous anodized aluminium oxide (AAO), the number of synthesized nanoribbons per unit area can be increased by 20-100 times. The mechanisms of formation and yield of the nanoribbons synthesized on AAO substrates having different arrangement and size of pores are analysed and discussed. It is shown that the yield and average length of the nanoribbons can base tuned by adjustment of the synthesis parameters. Analysis of magnetotransport measurements for the individual Bi₂Se₃ nanoribbons transferred on a Si/SiO₂ substrate show the presence of three different populations of charge carriers, originating from the Dirac surface states, bulk carriers and carriers from a trivial 2DEG from an accumulation layer at the Bi₂Se₃ nanoribbon interface with the substrate.