ORCID Profile
0000-0002-4639-5314
Current Organisations
IT University of Copenhagen
,
Københavns Universitet
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Publisher: American Physical Society (APS)
Date: 21-02-2018
Publisher: Wiley
Date: 26-04-2020
Publisher: American Chemical Society (ACS)
Date: 22-11-2021
Publisher: American Association for the Advancement of Science (AAAS)
Date: 21-04-2000
DOI: 10.1126/SCIENCE.288.5465.494
Abstract: Junctions consisting of two crossed single-walled carbon nanotubes were fabricated with electrical contacts at each end of each nanotube. The in idual nanotubes were identified as metallic (M) or semiconducting (S), based on their two-terminal conductances MM, MS, and SS four-terminal devices were studied. The MM and SS junctions had high conductances, on the order of 0.1 e 2 / h (where e is the electron charge and h is Planck's constant). For an MS junction, the semiconducting nanotube was depleted at the junction by the metallic nanotube, forming a rectifying Schottky barrier. We used two- and three-terminal experiments to fully characterize this junction.
Publisher: American Physical Society (APS)
Date: 05-02-2018
Publisher: IOP Publishing
Date: 05-2019
Abstract: We report MBE synthesis of InAs/vanadium hybrid nanowires. The vanadium was deposited without breaking ultra-high vacuum after InAs nanowire growth, minimizing any effect of oxidation and contamination at the interface between the two materials. We investigated four different substrate temperatures during vanadium deposition, ranging from -150 °C to 250 °C. The structural relation between vanadium and InAs depended on the deposition temperature. The three lower temperature depositions gave vanadium shells with a polycrystalline, granular morphology and the highest temperature resulted in vanadium reacting with the InAs nanowire. We fabricated electronic devices from the hybrid nanowires and obtained a high out-of-plane critical magnetic field, exceeding the bulk value for vanadium. However, size effects arising from the nanoscale grains resulted in the absence of a well-defined critical temperature, as well as device-to-device variation in the resistivity versus temperature dependence during the transition to the superconducting state.
Publisher: IOP Publishing
Date: 03-2017
Abstract: GaAs was central to the development of quantum devices but is rarely used for nanowire-based quantum devices with InAs, InSb and SiGe instead taking the leading role. p-type GaAs nanowires offer a path to studying strongly confined 0D and 1D hole systems with strong spin-orbit effects, motivating our development of nanowire transistors featuring Be-doped p-type GaAs nanowires, AuBe alloy contacts and patterned local gate electrodes towards making nanowire-based quantum hole devices. We report on nanowire transistors with traditional substrate back-gates and EBL-defined metal/oxide top-gates produced using GaAs nanowires with three different Be-doping densities and various AuBe contact processing recipes. We show that contact annealing only brings small improvements for the moderately doped devices under conditions of lower anneal temperature and short anneal time. We only obtain good transistor performance for moderate doping, with conduction freezing out at low temperature for lowly doped nanowires and inability to reach a clear off-state under gating for the highly doped nanowires. Our best devices give on-state conductivity 95 nS, off-state conductivity 2 pS, on-off ratio [Formula: see text], and sub-threshold slope 50 mV/dec at [Formula: see text] K. Lastly, we made a device featuring a moderately doped nanowire with annealed contacts and multiple top-gates. Top-gate sweeps show a plateau in the sub-threshold region that is reproducible in separate cool-downs and indicative of possible conductance quantisation highlighting the potential for future quantum device studies in this material system.
Publisher: American Physical Society (APS)
Date: 21-02-2018
Publisher: Royal Society of Chemistry (RSC)
Date: 2021
DOI: 10.1039/D0MH01070G
Abstract: We report fully monolithic, nanoscale logic elements featuring n- and p-type nanowires as electronic channels that are proton-gated by electron-beam patterned Nafion giving DC gain exceeding 5 and frequency response up to 2 kHz.
Publisher: American Chemical Society (ACS)
Date: 05-01-2017
DOI: 10.1021/ACS.NANOLETT.6B04075
Abstract: A key task in the emerging field of bioelectronics is the transduction between ionic rotonic and electronic signals at high fidelity. This is a considerable challenge since the two carrier types exhibit intrinsically different physics and are best supported by very different materials types-electronic signals in inorganic semiconductors and ionic rotonic signals in organic or bio-organic polymers, gels, or electrolytes. Here we demonstrate a new class of organic-inorganic transducing interface featuring semiconducting nanowires electrostatically gated using a solid proton-transporting hygroscopic polymer. This model platform allows us to study the basic transducing mechanisms as well as deliver high fidelity signal conversion by tapping into and drawing together the best candidates from traditionally disparate realms of electronic materials research. By combining complementary n- and p-type transducers we demonstrate functional logic with significant potential for scaling toward high-density integrated bioelectronic circuitry.
Publisher: American Chemical Society (ACS)
Date: 22-08-2018
DOI: 10.1021/ACS.NANOLETT.8B02249
Abstract: Difficulties in obtaining high-performance p-type transistors and gate insulator charge-trapping effects present two major challenges for III-V complementary metal-oxide semiconductor (CMOS) electronics. We report a p-GaAs nanowire metal-semiconductor field-effect transistor (MESFET) that eliminates the need for a gate insulator by exploiting the Schottky barrier at the metal-GaAs interface. Our device beats the best-performing p-GaSb nanowire metal-oxide-semiconductor field effect transistor (MOSFET), giving a typical subthreshold swing of 62 mV/dec, within 4% of the thermal limit, on-off ratio ∼10
Publisher: Springer Science and Business Media LLC
Date: 10-05-2021
Publisher: American Chemical Society (ACS)
Date: 04-11-2022
DOI: 10.1021/ACS.NANOLETT.2C02532
Abstract: Implementing superconductors capable of proximity-inducing a large energy gap in semiconductors in the presence of strong magnetic fields is a major goal toward applications of semiconductor/superconductor hybrid materials in future quantum information technologies. Here, we study the performance of devices consisting of InAs nanowires in electrical contact with molybdenum-rhenium (MoRe) superconducting alloys. The MoRe thin films exhibit transition temperatures of ∼10 K and critical fields exceeding 6 T. Normal/superconductor devices enabled tunnel spectroscopy of the corresponding induced superconductivity, which was maintained up to ∼10 K, and MoRe-based Josephson devices exhibited supercurrents and multiple Andreev reflections. We determine an induced superconducting gap lower than expected from the transition temperature and observe gap softening at finite magnetic field. These may be common features for hybrids based on large-gap, type II superconductors. The results encourage further development of MoRe-based hybrids.
No related grants have been discovered for Jesper Nygård.