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Author: Senkovskiy, B. × Has files: Yes ×

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Now showing 1 - 3 of 3
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    Tunneling current modulation in atomically precise graphene nanoribbon heterojunctions
    (London : Nature Publishing Group, 2021) Senkovskiy, B.; Nenashev, A.; Alavi, S.; Falke, Y.; Hell, M.; Bampoulis, P.; Rybkovskiy, D.; Usachov, D.; Fedorov, A.; Chernov, A.; Gebhard, F.; Meerholz, K.; Hertel, D.; Arita, M.; Okuda, T.; Miyamoto, K.; Shimada, K.; Fischer, F.; Michely, T.; Baranovskii, S.; Lindfors, K.; Szkopek, T.; Grüneis, A.
    Lateral heterojunctions of atomically precise graphene nanoribbons (GNRs) hold promise for applications in nanotechnology, yet their charge transport and most of the spectroscopic properties have not been investigated. Here, we synthesize a monolayer of multiple aligned heterojunctions consisting of quasi-metallic and wide-bandgap GNRs, and report characterization by scanning tunneling microscopy, angle-resolved photoemission, Raman spectroscopy, and charge transport. Comprehensive transport measurements as a function of bias and gate voltages, channel length, and temperature reveal that charge transport is dictated by tunneling through the potential barriers formed by wide-bandgap GNR segments. The current-voltage characteristics are in agreement with calculations of tunneling conductance through asymmetric barriers. We fabricate a GNR heterojunctions based sensor and demonstrate greatly improved sensitivity to adsorbates compared to graphene based sensors. This is achieved via modulation of the GNR heterojunction tunneling barriers by adsorbates.
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    Structural and electronic properties of epitaxial multilayer h-BN on Ni(111) for spintronics applications
    ([London] : Macmillan Publishers Limited, part of Springer Nature, 2016) Tonkikh, A.A.; Voloshina, E.N.; Werner, P.; Blumtritt, H.; Senkovskiy, B.; Güntherodt, G.; Parkin, S.S.P.; Dedkov, Yu. S.
    Hexagonal boron nitride (h-BN) is a promising material for implementation in spintronics due to a large band gap, low spin-orbit coupling, and a small lattice mismatch to graphene and to close-packed surfaces of fcc-Ni(111) and hcp-Co(0001). Epitaxial deposition of h-BN on ferromagnetic metals is aimed at small interface scattering of charge and spin carriers. We report on the controlled growth of h-BN/Ni(111) by means of molecular beam epitaxy (MBE). Structural and electronic properties of this system are investigated using cross-section transmission electron microscopy (TEM) and electron spectroscopies which confirm good agreement with the properties of bulk h-BN. The latter are also corroborated by density functional theory (DFT) calculations, revealing that the first h-BN layer at the interface to Ni is metallic. Our investigations demonstrate that MBE is a promising, versatile alternative to both the exfoliation approach and chemical vapour deposition of h-BN.
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    Atomically precise semiconductor-graphene and hBN interfaces by Ge intercalation
    (London : Nature Publishing Group, 2015) Verbitskiy, N.I.; Fedorov, A.V.; Profeta, G.; Stroppa, A.; Petaccia, L.; Senkovskiy, B.; Nefedov, A.; Wöll, C.; Usachov, D.Yu.; Vyalikh, D.V.; Yashina, L.V.; Eliseev, A.A.; Pichler, T.; Grüneis, A.
    The full exploration of the potential, which graphene offers to nanoelectronics requires its integration into semiconductor technology. So far the real-world applications are limited by the ability to concomitantly achieve large single-crystalline domains on dielectrics and semiconductors and to tailor the interfaces between them. Here we show a new direct bottom-up method for the fabrication of high-quality atomically precise interfaces between 2D materials, like graphene and hexagonal boron nitride (hBN), and classical semiconductor via Ge intercalation. Using angle-resolved photoemission spectroscopy and complementary DFT modelling we observed for the first time that epitaxially grown graphene with the Ge monolayer underneath demonstrates Dirac Fermions unaffected by the substrate as well as an unperturbed electronic band structure of hBN. This approach provides the intrinsic relativistic 2D electron gas towards integration in semiconductor technology. Hence, these new interfaces are a promising path for the integration of graphene and hBN into state-of-the-art semiconductor technology.