Browsing by Author "Kunakova, Gunta"

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    Relative Humidity Dependent Resistance Switching of Bi2S3 Nanowires
    (2017) Meija, Raimonds; Kunakova, Gunta; Prikulis, Juris; Varghese, Justin M.; Holmes, Justin D.; Erts, Donats
    Electrical properties of Bi2S3 nanowires grown using a single source precursor in anodic aluminum oxide templates are sensitive to the relative humidity in an inert gas environment. Dynamic sensing dependency is obtained and shows presence of spontaneous resistance switching effect between low and high relative humidity states. Employing the thermionic field emission theory, heights of Schottky barriers are estimated from the current-voltage characteristics and in relation to the humidity response. The change of Schottky barrier height is explained by local changes in physically adsorbed water molecules on the surface of the nanowire.
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    Surface structure promoted high-yield growth and magnetotransport properties of Bi2Se3 nanoribbons
    (2019-12-01) Kunakova, Gunta; Meija, Raimonds; Andzane, Jana; Malinovskis, Uldis; Petersons, Gvido; Baitimirova, Margarita; Bechelany, Mikhael; Bauch, Thilo; Lombardi, Floriana; Erts, Donats
    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.