| 1. |
- Liu, Ruisheng, et al.
(författare)
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Assembling ferromagnetic single-electron transistors by atomic force microscopy
- 2007
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Ingår i: Nanotechnology. - Bristol : Institute of Physics (IOP). - 0957-4484 .- 1361-6528. ; 18:5, s. 055302-
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Tidskriftsartikel (refereegranskat)abstract
- We demonstrate the assembly of nanoscale ferromagnetic single-electron transistors using atomic force microscopy for imaging as well as for nanoscale manipulation. A single 30 nm Au disc, forming the central island of the transistor, is manipulated with angstrom precision into the gap between a plasma-oxidized Ni source and drain electrodes. The tunnel resistances can be tuned in real time during the device fabrication by repositioning the Au disc. Transport measurements reveal long-term stable single-electron transistor characteristics at 4.2 K. The well-controlled devices with very small central islands facilitate future in-depth studies of the interplay between Coulomb blockade, spin-dependent tunnelling and spin accumulation in ferromagnetic single-electron transistors at elevated temperatures.
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| 2. |
- Liu, Ruisheng, et al.
(författare)
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Large magnetoresistance in Co/Ni/Co ferromagnetic single electron transistors
- 2007
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Ingår i: Applied Physics Letters. - New York : American Institute of Physics. - 0003-6951 .- 1077-3118. ; 90:12, s. 123111-
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Tidskriftsartikel (refereegranskat)abstract
- The authors report on magnetotransport investigations of nanoscaled ferromagnetic Co/Ni/Co single electron transistors. As a result of reduced size, the devices exhibit single electron transistor characteristics at 4.2 K. Magnetotransport measurements carried out at 1.8 K reveal tunneling magnetoresistance (TMR) traces with negative coercive fields, which the authors interpret in terms of a switching mechanism driven by the shape anisotropy of the central wirelike Ni island. A large TMR of about 18% is observed within a finite source-drain bias regime. The TMR decreases rapidly with increasing bias, which the authors tentatively attribute to excitation of magnons in the central island.
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| 3. |
- Liu, Ruisheng, et al.
(författare)
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Nanoscaled ferromagnetic single electron transistors
- 2007
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Ingår i: [Host publication title missing]. - Piscataway, N.J. : IEEE Press. ; 1-3, s. 420-423, s. 420-421
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- We report on a summary of fabricating and characterizing nanoscaled ferromagnetic single-electron transistors (F-SETs). One type of device is assembled with an atomic force microscope. A single 30 nm Au disc, forming the central island of the transistor, is manipulated with Angstrom precision into the gap between plasma oxidized Ni source and drain electrodes which are designed with different geometries to facilitate magnetic moment reversal at different magnetic fields. The tunnel resistances can be tuned in real-time during the device fabrication by re-positioning the An disc. A second type of device with Co electrodes and a central Au island is fabricated using a high-precision alignment procedure invoked during e-beam writing. Both devices exhibit single-electron transistor characteristics at 4.2K. From magnetotransport measurements carried out at 1.7K, we found that it is more efficient to realize spin injection and detection in Co/Au/Co devices fabricated with the second technique. A maximum TMR of about 4% was observed in these devices.
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| 4. |
- Pettersson, H., et al.
(författare)
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Assembling Ferromagnetic Single-electron Transistors with Atomic Force Microscopy
- 2008
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Ingår i: Nanostructures in electronics and photonics. - London : Pan Stanford Publishing. - 9789814241106 - 9789814241120 ; , s. 29-40
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Bokkapitel (refereegranskat)abstract
- Ferromagnetic Single Electron Transistors (F-SETs) comprise ferromagnetic electrodes connected to a ferromagnetic- or non-magnetic central island via tunnel barriers. These devices are important for studies of spin-transport physics in confined structures. Here we describe the development of a novel type of AFM-assembled nano-scale F-SETs suitable for spin-transport investigations at temperatures above 4.2 K. The ingenious fabrication technique means that their electrical characteristics can be tuned in real-time during the fabrication sequence by re-positioning the central island with Ångström precision.
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| 5. |
- Suyatin, Dmitry, et al.
(författare)
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Nano-Schottky contacts realized by bottom-up technique
- 2010
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Ingår i: INEC 2010 - 2010 3rd International Nanoelectronics Conference, Proceedings. - Piscataway, N.J. : IEEE Press. - 9781424435432 ; , s. 252-253
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Konferensbidrag (refereegranskat)abstract
- Properties of nanostructures realized by bottom-up techniques are often different from their bulk counterparts. Here we present a study of a nano-Schottky contact formed at the interface between a gold catalytic particle and an epitaxially grown GaxIn1-xAs/InAs nanowire. Selective electrical connections formed to the catalytic particle on one side and to the InAs segment on the other side allowed electrical and optical characterization of the formed junction. We demonstrate that the heterostructure region adjacent to the catalytic particle may act as an ultra-small volume unipolar photodetector with potentially ultra-fast response.
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| 6. |
- 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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