Electronic transport of Sb-doped Bi$_{2}$Se$_{3}$ topological insulator nanoribbons

Vapor-liquid-solid (VLS) grown nanoribbons, having large surface / volume ratio and high crystal quality, provide a unique opportunity to study topological insulator materials by electronic transport. However, clear observation of the surface states is often hindered due to materials' imperfections. Bulk impurities and environmental doping effects are known to contribute to dominant background transport signal, so that appropriate doping and surface protection are necessary to reduce the excess carriers. We report that Antimony (Sb), known to be an effective compensational dopant for bulk crystals, can be incorporated into Bi$_{2}$Se$_{3}$ nanoribbons and it reduces the bulk electron contribution significantly. With a Zinc Oxide protective layer, the carrier density of thin ribbons reaches below 10$^{12}$cm$^{-2}$. This talk will include magnetotransport studies and temperature dependant transport of nanoribbons as well.