| 1. |
- Abay, Simon, 1980, et al.
(författare)
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Quantized Conductance and Its Correlation to the Supercurrent in a Nanowire Connected to Superconductors
- 2013
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Ingår i: Nano Letters. - : American Chemical Society (ACS). - 1530-6992 .- 1530-6984. ; 13:8, s. 3614-3617
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Tidskriftsartikel (refereegranskat)abstract
- We report conductance and supercurrent of InAs nano wires coupled to Al-superconducting electrodes with short channel lengths and good Ohmic contacts. The nanowires are suspended 15 nm above a local gate electrode. The charge density in the nanowires can be controlled by a small change in the gate voltage. For large negative gate voltages, the number of conducting channels is reduced gradually, and we observe a stepwise decrease of both conductance and critical current before the conductance vanishes completely.
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| 2. |
- Suyatin, Dmitry, et al.
(författare)
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Strong Schottky barrier reduction at Au-catalyst/GaAs-nanowire interfaces by electric dipole formation and Fermi-level unpinning
- 2014
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Ingår i: Nature Communications. - London : Springer Science and Business Media LLC. - 2041-1723. ; 5
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Tidskriftsartikel (refereegranskat)abstract
- Nanoscale contacts between metals and semiconductors are critical for further downscaling of electronic and optoelectronic devices. However, realizing nanocontacts poses significant challenges since conventional approaches to achieve ohmic contacts through Schottky barrier suppression are often inadequate. Here we report the realization and characterization of low n-type Schottky barriers (~0.35 eV) formed at epitaxial contacts between Au-In alloy catalytic particles and GaAs-nanowires. In comparison to previous studies, our detailed characterization, employing selective electrical contacts defined by high-precision electron beam lithography, reveals the barrier to occur directly and solely at the abrupt interface between the catalyst and nanowire. We attribute this lowest-to-date-reported Schottky barrier to a reduced density of pinning states (~1017 m−2) and the formation of an electric dipole layer at the epitaxial contacts. The insight into the physical mechanisms behind the observed low-energy Schottky barrier may guide future efforts to engineer abrupt nanoscale electrical contacts with tailored electrical properties.
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| 3. |
- Abay, Simon, 1980, et al.
(författare)
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High Critical-Current Superconductor-InAs Nanowire-Superconductor Junctions
- 2012
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Ingår i: Nano Letters. - : American Chemical Society (ACS). - 1530-6992 .- 1530-6984. ; 12:11, s. 5622-5625
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Tidskriftsartikel (refereegranskat)abstract
- We report on the fabrication of InAs nanowires coupled to superconducting leads with high critical current and widely tunable conductance. We implemented a double lift off nanofabrication Method to get very short nanowire devices with Ohmic contacts. We observe very high critical. currents of up to 800 nA in a wire with a diameter of 80 nm. The current- voltage characteristics of longer and suspended nanowires display,either. Coulomb blockade or supercurrent depending on a local gate voltage, combining different regimes of transport in a single device.
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| 4. |
- Abdel, Naseem, et al.
(författare)
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Fabrication and Characterization of Ultra-Thin PIN Silicon Detectors for Counting the Passage of MeV Ions
- 2013
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Ingår i: IEEE Transactions on Nuclear Science. - 0018-9499. ; 60:2, s. 1182-1188
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Tidskriftsartikel (refereegranskat)abstract
- This paper describes the fabrication and initial characterization of an ultra-thin silicon PIN detector using a new technique in silicon nanotechnology. In collaboration with the Nuclear Physics Division and the Lund Nano Lab at Lund University, we have developed and manufactured ultra thin Delta E-detectors for spectroscopic applications. The fabrication process has been carried out using a double-polished silicon substrate n-type wafer and locally thinning by means of a 10:1 solution of 25% tetramethyl ammonium hydroxide (TMAH) with Isopropyl alcohol. More than 100 detectors of different thicknesses, down to 5 mu m with active areas ranging from 0.71 to 0.172 mm(2), have been fabricated. The main design considerations of our thin detectors were a very low leakage current below 12 nA and a low full depletion voltage at a reverse bias less than 1.5 V. Finally, most of our thin detectors offer an energy resolution (FWHM) as low as 31 keV for 5.487 MeV alpha particles from a Am-241 source.
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| 5. |
- Abdel, N. S., et al.
(författare)
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Efficient ultra-thin transmission silicon detectors for a single-ion irradiation system at the Lund Ion Beam Analysis Facility
- 2014
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Ingår i: Journal of Instrumentation. - 1748-0221. ; 9
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Tidskriftsartikel (refereegranskat)abstract
- This paper describes the fabrication of efficient ultra-thin silicon transmission detectors for use as pre-cell detectors in single-ion experiments on living cells at the Lund Ion Beam Analysis Facility. More than 40 detectors of different thicknesses down to 5 mu m have been fabricated and packaged. The main design considerations were very low leakage current (below 9 nA) and low full depletion voltage at biases less than 0.5 V at room temperature. In addition, we have shown that cooling the device can reduce the leakage current to 3 nA. The experimental testing of the pre-cell detection system is based on counting the passage of ions through the transmission (Delta E) detector before hitting the stopping (E) detector placed behind it, to ensure the accurate delivery of specific doses of radiation to the sample. Optimal detection of the fabricated detectors for the passage of an external beam of 2.2 MeV protons was obtained by cooling the device to below 2 degrees C. Cooling the Delta E detectors provides up to 20% better energy resolution and up to 98% detection efficiency for 2.2 MeV protons. The development of this kind of efficient pre-cell detector enables a range of new experiments to be conducted on thick biological samples.
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| 6. |
- Adolfsson, Karl, et al.
(författare)
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Fluorescent Nanowire Heterostructures as a Versatile Tool for Biology Applications
- 2013
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Ingår i: Nano Letters. - : American Chemical Society (ACS). - 1530-6992 .- 1530-6984. ; 13:10, s. 4728-4732
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Tidskriftsartikel (refereegranskat)abstract
- Nanowires are increasingly used in biology, as sensors, as injection devices, and us model systems for toxicity studies. Currently, in situ visualization of nanowires in biological media is done using organic dyes, which a;:e prone to photobleaching, or using microscopy methods which either yield poor resolution or require a sophisticated setup. Here we show that inherently fluorescent nanowire axial heterostructnies c:an be used to localize and identify nanowires in cells and tissue; By synthesizing GaP GaInP nanowire heterostructures, with nonfluorescent GaP segments and fluorescent GaInP segments, we created a barcode labeling system enabling the distinction of the nanowire morphological and chemical properties using fluorescence microscopy. The GaInP photoluminescence stability, combined with the fact that the nanowires can be coated with different materials while retaining their fluorescence, make these nanowires promising tools for biological and nanotoxicological studies.
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| 7. |
- Adolfsson, Karl, et al.
(författare)
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Ingestion of gallium phosphide nanowires has no adverse effect on Drosophila tissue function.
- 2013
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Ingår i: Nanotechnology. - : IOP Publishing. - 0957-4484 .- 1361-6528. ; 24:28
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Tidskriftsartikel (refereegranskat)abstract
- Engineered nanoparticles have been under increasing scrutiny in recent years. High aspect ratio nanoparticles such as carbon nanotubes and nanowires have raised safety concerns due to their geometrical similarity to asbestos fibers. III-V epitaxial semiconductor nanowires are expected to be utilized in devices such as LEDs and solar cells and will thus be available to the public. In addition, clean-room staff fabricating and characterizing the nanowires are at risk of exposure, emphasizing the importance of investigating their possible toxicity. Here we investigated the effects of gallium phosphide nanowires on the fruit fly Drosophila melanogaster. Drosophila larvae and/or adults were exposed to gallium phosphide nanowires by ingestion with food. The toxicity and tissue interaction of the nanowires was evaluated by investigating tissue distribution, activation of immune response, genome-wide gene expression, life span, fecundity and somatic mutation rates. Our results show that gallium phosphide nanowires applied through the diet are not taken up into Drosophila tissues, do not elicit a measurable immune response or changes in genome-wide gene expression and do not significantly affect life span or somatic mutation rate.
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| 8. |
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| 9. |
- Albinsson, Bo, 1963, et al.
(författare)
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Electron Transfer Through Butadiyne-Linked Porphyrin-Based Molecular Wires
- 2012
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Ingår i: Multiporphyrin Arrays: Fundamentals and Applications. - : Pan Stanford Publishing. - 9789814364287 ; , s. 55-90
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- Electron transfer is of fundamental importance in many areas of chemistry and biochemistry [1]. The ability to transfer charge efficiently over distances in the 10 nm range is crucial in various practical devices, such as organic transistors and solar cells both dye-sensitized metal oxide solar cells and bulk-heterojunction blend devices [2]. Furthermore, in the context of the ever-decreasing dimensions of integrated circuits, it is interesting to study charge transport through individual molecules [3]. Organic π -conjugated oligomers and polymers are attractive candidates as molecularwires, because modern synthetic chemistry can be used to create almost any type of π -conjugated backbone, while non-covalent interactions and supramolecular chemistry can be used to modify the backbone conformation. Interactions of conjugated oligomers, both with each other and with the external environment, can also be controlled by self-assembly and non-covalent encapsulation.
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| 10. |
- Andersen, Karsten Brandt, et al.
(författare)
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Stability of diphenylalanine peptide nanotubes in solution
- 2011
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Ingår i: Nanoscale. - : Royal Society of Chemistry (RSC). - 2040-3372 .- 2040-3364. ; 3:3, s. 994-998
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Tidskriftsartikel (refereegranskat)abstract
- Over the last couple of years, self-organizing nanotubes based on the dipeptide diphenylalanine have received much attention, mainly as possible building blocks for the next generation of biosensors and as drug delivery systems. One of the main reasons for this large interest is that these peptide nanotubes are believed to be very stable both thermally and chemically. Previously, the chemical and thermal stability of self-organizing structures has been investigated after the evaporation of the solvent. However, it was recently discovered that the stability of the structures differed significantly when the tubes were in solution. It has been shown that, in solution, the peptide nanotubes can easily be dissolved in several solvents including water. It is therefore of critical importance that the stability of the nanotubes in solution and not after solvent evaporation be investigated prior to applications in which the nanotube will be submerged in liquid. The present article reports results demonstrating the instability and suggests a possible approach to a stabilization procedure, which drastically improves the stability of the formed structures. The results presented herein provide new information regarding the stability of self-organizing diphenylalanine nanotubes in solution.
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