In this work, stoichiometric separate bismuth selenide (Bi 2 Se 3 ) nanoplates and continuous Bi 2 Se 3 coatings are synthesized on graphene substrate by catalystfree vapor-solid deposition method. The orientation of synthesized nanoplates relative to the substrate surface varies from heteroepitaxial (planar) to oriented under different angles (non-planar). The non-planar growth of the nanoplates was achieved for the first time by short-term carrier inert gas flow in certain temperature interval of the synthesis process. The crystallographic growth directions of non-planar nanoplates were determined from HRTEM images as well as estimated from the slope angles of non-planar nanoplates. Bi 2 Se 3 coatings consisting of combination of planar and non-planar nanoplates exhibit significantly enhanced in comparison with coating consisting of only planar coalescent Bi 2 Se 3 nanoplates thermoelectric properties. Demonstrated graphene/Bi 2 Se 3 /graphene devices may find applications in thermoelectric and photo-detection sensors.

In the present work, a catalyst-free physical vapour deposition method is used to synthesize high yield of Bi 2 Se 3 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 Bi 2 Se 3 nanoribbons transferred on a Si/SiO 2 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 Bi 2 Se 3 nanoribbon interface with the substrate.