| 1. |
- Ganjipour, Bahram, et al.
(författare)
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GaSb nanowire single-hole transistor
- 2011
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 99:26
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Tidskriftsartikel (refereegranskat)abstract
- We present an experimental study of single hole transistors (SHTs) made from p-type GaSb nanowires. Closely spaced source-drain electrodes are fabricated onto GaSb nanowires to define a SHT within a GaSb nanowire. Room temperature back-gate transfer characteristics show typical hole transport behavior. The fabricated devices are characterized by transport measurements at 1.5 K, where periodic conductance oscillations due to Coulomb blockade are observed and a charging energy of 5 meV is determined. (C) 2011 American Institute of Physics. [doi:10.1063/1.3673328]
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| 2. |
- Gustafson, Boel, et al.
(författare)
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Coupling between lateral modes in a vertical resonant tunneling structure
- 2002
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Ingår i: Physica E: Low-Dimensional Systems and Nanostructures. - 1386-9477. ; 13:2-4, s. 950-953
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Tidskriftsartikel (refereegranskat)abstract
- We present experimental results and theoretical calculations of the vertical electron transport through a laterally constricted resonant tunneling transistor. Current-voltage measurements at 4.2 K show numerous current peaks that exhibit a complex dependence on the applied gate voltage. A scattering-matrix approach combined with the Landauer formalism was used to perform quantum mechanical calculations of the electron transport through a quantum dot structure with laterally confined emitter and collector regions. The simulations qualitatively reproduce the measured data, suggesting a strong coupling between the lateral modes in the quantum dot and the collector
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| 3. |
- Lewen, R., et al.
(författare)
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High frequency characterization of a GaInAs/InP electronic waveguide T-branch switch
- 2002
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Ingår i: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 91:4, s. 2398-2402
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Tidskriftsartikel (refereegranskat)abstract
- We report comprehensive microwave measurements on a T-branch switch; a GaInAs/InP electron waveguide based structure. The study includes a small signal model of the device where limitations of high frequency operation are discussed. An example of large signal operation where the nonlinearity of the device is exploited by operating the T-branch switch as a frequency multiplier is demonstrated.
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| 4. |
- Maximov, Ivan, et al.
(författare)
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Nanoimprint lithography for fabrication of three-terminal ballistic junctions in InP/GaInAs
- 2002
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Ingår i: Nanotechnology. - : IOP Publishing. - 0957-4484. ; 13:5, s. 666-668
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Tidskriftsartikel (refereegranskat)abstract
- We present processing technology and characterization results for InP/GaInAs two-dimensional electron gas (2DEG) three-terminal ballistic junction (TBJ) devices manufactured using nanoimprint lithography (NIL). To transfer sub-100 nm features into a high-mobility InP-based 2DEG material, we used SiO2/Si stamps made using electron beam lithography and reactive ion etching. After NIL, the resist residues are removed in oxygen plasma; this is followed by wet etching of InP/GaInAs to define the TBJ structures. Fabricated TBJ devices are characterized using scanning electron microscopy and electron transport measurements. Highly non-linear electrical characteristics as predicted by the theory (Xu H Q 2001 APPI. Phys. Lett. 78 2064) are demonstrated.
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| 5. |
- Maximov, Ivan, et al.
(författare)
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Nanoimprint technology for fabrication of three-terminal ballistic junction devices in GaInAs/InP
- 2003
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Ingår i: Microelectronic Engineering. - 1873-5568. ; 67-8, s. 196-202
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Tidskriftsartikel (refereegranskat)abstract
- We present processing technology based on nanoimprint lithography (NIL) and wet etching for fabrication of GaInAs/InP three-terminal ballistic junction (TBJ) devices. To transfer sub-100 nm features into a high-mobility InP-based 2DEG material, we used SiO2/Si stamps made with electron beam lithography and reactive ion etching. After the NIL, the resist residues are removed in oxygen plasma followed by wet etching of GaInAs/InP to define the M-structures. Fabricated TBJ-devices are characterized using scanning electron microscopy and electron transport measurements. Highly non-linear electrical characteristics of the TBJ structures are demonstrated and compared with E-beam defined devices. (C) 2003 Elsevier Science B.V. All rights reserved.
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| 6. |
- Nilsson, Henrik, et al.
(författare)
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Correlation-induced conductance suppression at level degeneracy in a quantum dot.
- 2010
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Ingår i: Physical Review Letters. - 1079-7114. ; 104:18
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Tidskriftsartikel (refereegranskat)abstract
- The large, level-dependent g factors in an InSb nanowire quantum dot allow for the occurrence of a variety of level crossings in the dot. While we observe the standard conductance enhancement in the Coulomb blockade region for aligned levels with different spins due to the Kondo effect, a vanishing of the conductance is found at the alignment of levels with equal spins. This conductance suppression appears as a canyon cutting through the web of direct tunneling lines and an enclosed Coulomb blockade region. In the center of the Coulomb blockade region, we observe the predicted correlation-induced resonance. Our findings are supported by numerical and analytical calculations.
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| 7. |
- Nilsson, Henrik, et al.
(författare)
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Giant, level-dependent g factors in InSb nanowire quantum dots.
- 2009
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Ingår i: Nano Letters. - : American Chemical Society (ACS). - 1530-6992 .- 1530-6984. ; 9:9, s. 3151-3156
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Tidskriftsartikel (refereegranskat)abstract
- We report on magnetotransport measurements on InSb nanowire quantum dots. The measurements show that the quantum levels of the InSb quantum dots have giant g factors, with absolute values up to approximately 70, the largest value ever reported for semiconductor quantum dots. We also observe that the values of these g factors are quantum level dependent and can differ strongly between different quantum levels. The presence of giant g factors indicates that considerable contributions from the orbital motion of electrons are preserved in the measured InSb nanowire quantum dots, while the level-to-level fluctuations arise from spin-orbit interaction. We have deduced a value of Delta(SO) = 280 mueV for the strength of spin-orbit interaction from an avoided level crossing between the ground state and first excited state of an InSb nanowire quantum dot with a fixed number of electrons.
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| 8. |
- Nilsson, Henrik, et al.
(författare)
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InSb Nanowire Field-Effect Transistors and Quantum-Dot Devices
- 2011
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Ingår i: IEEE Journal of Selected Topics in Quantum Electronics. - 1077-260X. ; 17:4, s. 907-914
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Tidskriftsartikel (refereegranskat)abstract
- The authors present fabrication and electrical measurements of InSb nanowire field-effect transistors (FETs) and quantum dots. The devices are made on a SiO2-capped Si substrate from InSb segments of InAs/InSb heterostructured nanowires, which are grown by metalorganic vapor phase epitaxy. For the FETs, both single- and dual-gate devices are fabricated. The Si substrate is employed as the back gate in both the single-and dual-gate devices, while a top metal gate is employed as a second gate in the dual-gate devices. This top gate is made either as a global gate or as a local finger gate by using a thin HfO2 layer grown by atomic layer deposition as a gate dielectric. The measurements reveal that the fabricated devices show the desired transistor characteristics. The measurements also demonstrate the possibility of realizing ambipolar transistors using InSb nanowires. For InSb nanowire quantum dots, both contact-induced Schottky-barrier-defined devices and top-finger-gate-defined devices are fabricated, and the Si substrate is used as a gate to tune the electron number in the quantum dots. The electrical measurements of these fabricated quantum-dot devices show the Coulomb-blockade effect at 4.2 K. A Fabry-Perot-like interference effect is also observed in a Schottky-barrier-defined quantum device. The authors also discuss in a comparative way, the results of measurements for the InSb nanowire devices made by different fabrication technologies employed in this study.
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| 9. |
- Anttu, Nicklas, et al.
(författare)
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Optical Far-Field Method with Subwavelength Accuracy for the Determination of Nanostructure Dimensions in Large-Area Samples.
- 2013
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Ingår i: Nano Letters. - : American Chemical Society (ACS). - 1530-6992 .- 1530-6984. ; 13:6, s. 2662-2667
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Tidskriftsartikel (refereegranskat)abstract
- The physical, chemical, and biological properties of nanostructures depend strongly on their geometrical dimensions. Here we present a fast, noninvasive, simple-to-perform, purely optical method that is capable of characterizing nanostructure dimensions over large areas with an accuracy comparable to that of scanning electron microscopy. This far-field method is based on the analysis of unique fingerprints in experimentally measured reflectance spectra using full three-dimensional optical modeling. We demonstrate the strength of our method on large-area (millimeter-sized) arrays of vertical InP nanowires, for which we simultaneously determine the diameter and length as well as cross-sample morphological variations thereof. Explicitly, the diameter is determined with an accuracy better than 10 nm and the length with an accuracy better than 30 nm. The method is versatile and robust, and we believe that it will provide a powerful and standardized measurement technique for large-area nanostructure arrays suitable for both research and industrial applications.
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| 10. |
- Balocco, C, et al.
(författare)
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Microwave detection at 110 GHz by nanowires with broken symmetry
- 2005
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Ingår i: Nano Letters. - : American Chemical Society (ACS). - 1530-6992 .- 1530-6984. ; 5:7, s. 1423-1427
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Tidskriftsartikel (refereegranskat)abstract
- By using arrays of nanowires with intentionally broken symmetry, we were able to detect microwaves up to 110 GHz at room temperature. This is, to the best of our knowledge, the highest speed that has been demonstrated in different types of novel electronic nanostructures to date. Our experiments showed a rather stable detection sensitivity over a broad frequency range from 100 MHz to 110 GHz. The novel working principle enabled the nanowires to detect microwaves efficiently without a dc bias. In principle, the need for only one high-resolution lithography step and the planar architecture allow an arbitrary number of nanowires to be made by folding a linear array as many times as required over a large area, for example, a whole wafer. Our experiment on 18 parallel nanowires showed a sensitivity of approximately 75 mV dc output/mW of nominal input power of the 110 GHz signal, even though only about 0.4% of the rf power was effectively applied to the structure because of an impedance mismatch. Because this array of nanowires operates simultaneously, low detection noise was achieved, allowing us to detect -25 dBm 110 GHz microwaves at zero bias with a standard setup.
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