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  • 1
    Electronic Resource
    Electronic Resource
    Transport characteristics of AlGaAs/GaAs wires fabricated by focused Ga-ion-beam implantation (1991)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 69 (1991), S. 3633-3640 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Electron transport was studied in AlGaAs/GaAs wires fabricated using focused Ga-ion-beam implantation. Single-wire samples 0.2–10 μm wide and 20 μm long were prepared with various ion doses ranging 2×1011–4×1012 cm−2; multiple-wire samples 0.1–0.3 μm wide and 10 μm long were prepared with an ion dose of 2×1011 cm−2. Electron mobility is reduced in the narrow wires because of the implantation-induced damage, and this mobility degradation is diminished by reducing the ion dose. These behaviors are consistently explained in terms of a diffusive scattering effect inside the channel and at the sidewall of the channel. Mobility in wires with the 2×1011 cm−2 ions is predominantly determined by the sidewall specularity. A 0.2-μm-wide wire with this ion dose exhibits a mobility of 2×105 cm2/(V s) and a specularity above 0.8. These values exceed those previously reported for wires fabricated using ion implantation and probably arise from the annealing employed in the present work. Conductance steps are observed with a single 0.2-μm-wide wire, and enhanced transconductance steps occur in multiple-wire samples. These behaviors are related to mobility modulation that occurs when one-dimensional subbands cross the Fermi level.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.348510
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  • 2
    Electronic Resource
    Electronic Resource
    Strong negative transconductance in in-plane-gate transistors written by focused-ion-beam implantation (1994)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 75 (1994), S. 7573-7575 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: A strong negative transconductance is investigated in in-plane-gate transistors written by focused-ion-beam implantation in the two-dimensional electron gas in modulation-doped AlGaAs/GaAs heterostructures. This occurs in a configuration where two in-plane gates G1 and G2 used to control the current through a channel lying between them are biased with different voltages Vg1 and Vg2. When the voltage Vg2〈0 is held constant, the current through the channel can be reduced to zero by increasing Vg1 beyond a critical value. In an earlier study this effect was attributed to velocity modulation. It is found, however, that in this regime Vg1 causes a very small current Ig2 to flow across gate G2. It is observed that changes in Id are correlated to changes in Ig2 and thus conclude that Ig2 is responsible for the strong negative transconductance.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.356610
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  • 3
    Electronic Resource
    Electronic Resource
    Enhanced collimation in narrow channels fabricated by focused-ion-beam implantation (1994)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 75 (1994), S. 2477-2480 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We investigate the collimation factor of narrow channels defined by focused-ion-beam insulation writing in the highly mobile two-dimensional electron gas of an AlGaAs/GaAs heterostructure. We show that the degree of collimation can be enhanced by appropriate channel design. Additional boundary roughness caused by selective implantation of ions along the channel boundary considerably increases the collimation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.356245
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  • 4
    Electronic Resource
    Electronic Resource
    Ballistic electron transport in macroscopic four-terminal square structures with high mobility (1991)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 58 (1991), S. 2672-2674 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Ballistic electron transport characteristics are studied using macroscopic four-terminal square structures formed in high-mobility wafers (μ=7.8×106 cm2/V s at 1.5 K). Ballistic transport over 200 μm can be detected as a negative peak in resistance around B=0 T when four-terminal resistance is measured as a function of magnetic field. The ballistic mean free path (lb) of electrons is evaluated from the size dependence of the negative peak height. The estimated lb becomes 86 μm, which is approximately equal to a conventional mean free path calculated from carrier density and mobility of the wafer.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.104803
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  • 5
    Electronic Resource
    Electronic Resource
    Effects of coupling and nonresonant tunneling on Coulomb blockade oscillations in an asymmetric double dot structure (1997)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 71 (1997), S. 2499-2501 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We report on single electron transport through an asymmetric double dot structure with well-defined dot potential profiles. As the two dots are coupled, the conductance exhibits two pronounced types of Coulomb blockade oscillations. An analysis of the small short-period oscillations indicates the presence of interdot interaction. When the coupling strength is reduced, the oscillations become few irregular peaks but they develop into periodic oscillations again as the drain voltage is increased to 0.6 mV. This appearance with increasing drain voltage is well explained by our model which is based on the stochastic Coulomb blockade model and nonresonant tunneling. © 1997 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.120100
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  • 6
    Electronic Resource
    Electronic Resource
    Low-frequency noise in very high mobility modulation-doped structures (1992)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 61 (1992), S. 2926-2928 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We report here on the observation of low-frequency (1–100 Hz) noise characteristics as a function of current in very high mobility four-terminal structures at 4.2 K. At low currents, the noise levels are too low to be observed with our measurement system. When the mobility is decreased by a change in gate voltage, or when the injected current is increased, noise levels increased. At currents where excess noise is observable, the channel current-voltage characteristics are nonlinear and the noise current dependence is superquadratic. The steep current-dependence results from the degradation of mobility due to electron heating, with the subsequent rapid noise increase due to optical phonon scattering.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.108024
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  • 7
    Electronic Resource
    Electronic Resource
    High temperature ballistic transport observed in AlGaAs/InGaAs/GaAs small four-terminal structures (1993)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 63 (1993), S. 2366-2368 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Four-terminal structures are fabricated by focused-ion-beam (FIB) scanning on an AlGaAs/InGaAs/GaAs modulation doped structure. The large carrier density of this system results in small depletion spreading and a 260-nm-square four-terminal structure is successfully formed. The bend resistance of this structure indicates that ballistic coupling between two facing terminals remains up to room temperature. Thermal broadening of electron energy enhances the ballistic nature of the system at high temperature.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.110799
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  • 8
    Electronic Resource
    Electronic Resource
    Effects of finite drain voltage and finite temperature on coherent resonant transport in single electron tunneling regime (1996)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 69 (1996), S. 406-408 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Effects of a finite drain voltage and a finite temperature on coherent transport in the single electron tunneling regime are investigated for a novel quantum dot structure defined by two shallow etched trenches and two line Schottky gates. A regular amplitude modulation of Coulomb blockade oscillations is observed and attributed to coherent resonant transport. Increasing drain voltage disturbs the amplitude modulation more significantly than raising the temperature. This is explained in terms of the effects of nonmonochromatic electrons on the interference condition. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.118076
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  • 9
    Electronic Resource
    Electronic Resource
    Kondo effect in an integer-spin quantum dot (2000)
    [s.l.] : Macmillian Magazines Ltd.
    Nature 405 (2000), S. 764-767 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] The Kondo effect—a many-body phenomenon in condensed-matter physics involving the interaction between a localized spin and free electrons—was discovered in metals containing small amounts of magnetic impurities, although it is now recognized to be of fundamental importance in a ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/35015509
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  • 10
    Electronic Resource
    Electronic Resource
    Quantum interference in electron collision (1998)
    [s.l.] : Macmillan Magazines Ltd.
    Nature 391 (1998), S. 263-265 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] The indistinguishability of identical quantum particles can lead to quantum interferences that profoundly affect their scattering. If two particles collide and scatter, the process that results in the detection of the first particle in one direction and the second particle in another ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/34611
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