Substrate-Independent Catalyst-Free Synthesis of High-Purity Bi2Se3 Nanostructures

We describe a catalyst-free vapor-solid synthesis of bismuth selenide (Bi2Se3) nanostructures at ambient pressure with hydrogen as a carrier gas. The nanostructures were synthesized on glass, silicon and mica substrates and the method yields a variety of nanostructures: nanowires, nanoribbons, nanoplatelets and nanoflakes. The materials analysis shows high chemical purity in all cases, without sacrificing the crystalline structure of Bi2Se3. Low-temperature measurements of the nanostructures indicate contributions from the surface states with a tunable carrier density. Samples synthesized on flexible mica substrates show no significant change in resistance upon bending, indicating robustness of as-grown Bi2Se3 nanostructures and their suitability for device applications.