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  • 1
    Electronic Resource
    Electronic Resource
    Plasmon excitation and self-coupling in a bi-periodically modulated two-dimensional electron gas (1992)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 71 (1992), S. 6049-6061 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We report far infrared (FIR) studies of plasmons in spatially modulated two-dimensional electron gases (2DEGs) in AlGaAs/GaAs heterostructures using biased overlaid metal gratings, including interdigitated gratings, both as optical couplers and as spatially modulating gates. Comparison of the experimental results with the predictions of scattering matrix calculations of the FIR response of a modulated 2DEG in the presence of a perfectly conducting lamellar grating allow us to deduce the spatial variation of the number density distribution in the 2DEG as a function of grating bias. For the interdigitated grating gates, the 2DEG can be modulated at a period of twice that of the grating fingers by differentially biasing alternate fingers; 2D plasmon resonances have been observed at half-integral values of the grating wave vector G, corresponding to the electrically induced periodicity of the 2DEG modulation itself acting as an optical coupler in addition to the metal grating. The observed G/2 plasmon frequencies decrease with increasing amplitude of the 2DEG number density modulation, in quantitative agreement with those obtained from scattering matrix calculations of the optical response of a modulated 2DEG under a perfectly conducting lamellar grating; calculations of the oscillating charge density profiles show that this occurs because, as the modulation amplitude increases, the oscillation becomes localized in regions of low 2DEG number density which are also under one of the sets of grating fingers, and is therefore better screened.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.350462
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  • 2
    Electronic Resource
    Electronic Resource
    Domain wall trapping in controlled submicron ferromagnetic elements (2000)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 87 (2000), S. 4727-4729 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The domain configuration in permalloy wires (30 nm thick, 10 μm wide, and 205 μm long) with a wide size range of a narrow central bridge (5 μm long and w μm wide; 0.5≤w≤10 μm) were investigated in both their demagnetized and remanent states using magnetic force microscopy and the results were confirmed by micromagnetic calculations. At the bridge region, domain walls were found to be shifted by a small external field. Scanning magneto-optical Kerr effect revealed that the coercivity in these structures are the same as that in a straight wire, suggesting that domain wall movement is the dominant process in the magnetization reversal of these structures. © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.373140
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  • 3
    Electronic Resource
    Electronic Resource
    Domain nucleation processes in mesoscopic Ni80Fe20 wire junctions (2000)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 87 (2000), S. 3032-3036 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The magnetization reversal process in permalloy (Ni80Fe20) wire junction structures has been investigated using magnetoresistance (MR) measurements and scanning Kerr microscopy. A combination of electron beam lithography and a lift-off process has been utilized to fabricate wires consisting of two 200 μm length regions with distinct widths w1 and w2 in the range 1–5 μm. Longitudinal MR measurements and magneto-optic Kerr effect hysteresis loops demonstrate that the magnetization reversal of the complete structure is predominantly determined by the wider region for fields applied parallel to the wire axis. Magnetic force microscopy and micromagnetic calculations show that several domain walls nucleate in the wider part and are trapped in the junction area. This implies that domain nucleation at the junction of the wire initiates magnetization reversal in the narrow half. As a consequence, the switching fields are found to be identical in both halves in this case. These results suggest the possibility of designing structures which can be used to "launch" reverse domains in narrow wires within a controlled field range. © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.372295
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  • 4
    Electronic Resource
    Electronic Resource
    Measurement of the sheet resistance of resistive films on thin substrates from 120 to 175 GHz using dielectric waveguides (2002)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 91 (2002), S. 2547-2549 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: A method is reported for the measurement of the sheet resistance, at microwave frequencies, of conducting films supported on thin dielectric substrates. The sheet resistance is found from measurements of the millimeter-wave power transmission through the film using a millimeter-wave source and power meter coupled through dielectric waveguides. The accuracy of this technique does not depend on the precise placement of the waveguide terminations with respect to the substrate, in contrast to methods using metallic waveguides or coils. This method is used to characterize the sheet resistance of semiconductor samples in the frequency range 120–175 GHz and the results are compared to the dc values obtained by conventional techniques. Sheet resistance values can be easily measured by this method in the range from 1 to 1000 Ω. © 2002 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1430534
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  • 5
    Electronic Resource
    Electronic Resource
    Finite size effects in the static and dynamic magnetic properties of FeNi wire array structures : The 41st annual conference on magnetism and magnetic materials (1997)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 81 (1997), S. 5452-5454 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We report on systematic studies of both the static and dynamic properties of FeNi wire arrays on GaAs(001) substrates. The wires were between 0.4 and 10 μm wide and were separated by twice their width. The static magnetic properties were investigated using magneto optical Kerr effect magnetometry. The dynamical magnetic properties (spin-waves) were investigated by Brillouin light scattering in the Voigt geometry. With an external field applied along the hard shape axis, the saturation field was observed to increase and the spin-wave energies decreased with decreasing wire size. For fields applied along the (easy) axis of the wire, we observed an increase in the coercive field as the width of the wire is decreased. The frequency of the surface mode was found to increase with decreasing wire size while the first volume mode frequency was found to be wire size independent. © 1997 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.364567
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  • 6
    Electronic Resource
    Electronic Resource
    Dynamic scaling of magnetic hysteresis in micron-sized Ni80Fe20 disks (1999)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 74 (1999), S. 1609-1611 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The scaling of the magnetic hysteresis loop area of permalloy disks (20–400 μm diam) has been studied as a function of applied field amplitude H0 and frequency Ω using scanning Kerr microscopy. An increase in the dynamic coercivity with reduced size is observed for d〈100 μm in the frequency range studied (0.1–800 Hz). However, the loop area A follows the scaling relation A∝H0αΩβ, with α(approximate)0.14 and β(approximate)0.50 throughout the entire size range studied. Our results demonstrate that the dynamic scaling behavior is universal even though the lateral size influences the domain structure and magnetic reversal behavior. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.123632
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  • 7
    Electronic Resource
    Electronic Resource
    Fabrication of free-standing single-crystal silicon wires (1988)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 52 (1988), S. 834-835 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: A fabrication process for free-standing single-crystal silicon wires of submicrometer cross-sectional dimensions and lengths in excess of 40 μm is reported. The starting material is silicon-on-insulator that has been recrystallized using a dual electron beam recrystallizing system. The wires are then fabrictaed in the recrystallized layer by a combination of electron beam lithography and plasma etching. Electrical measurements have been performed and the fabrication limits of the process are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.99299
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  • 8
    Electronic Resource
    Electronic Resource
    Electron beam system for rapid isothermal annealing of semiconductor materials and devices (1985)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 56 (1985), S. 1257-1261 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: An isothermal processing system using a 2-kW electron beam is described. Processing of areas up to 4×4 in. is achieved by rapidly scanning the beam in the multiple scan mode. An analysis of this method and some typical heating cycles for silicon wafers are presented. There is good agreement between theoretically predicted and experimentally measured temperatures. Additionally, closed-loop operation is demonstrated where an optical pyrometer is used to control the electron beam current. This machine can either process whole wafers, or can sequentially treat a large number of small chips. This enables, for example, the rapid assessment of the annealing behavior of a particular implant by processing chips, cut from the same wafer, under varying conditions. Heating cycles of a fraction of a second to tens of seconds or more, which are not possible with furnaces, at temperatures up to 1000°C or greater have found many applications in semiconductor processing. Two important uses are described in this paper illustrating the potential of the technique. One is the annealing of an arsenic implant in silicon with negligible diffusion and the other is the controlled drive in of arsenic.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1137987
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  • 9
    Electronic Resource
    Electronic Resource
    Hopping conduction in a free-standing GaAs-AlGaAs heterostructure wire (1993)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 62 (1993), S. 2533-2535 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We report on the fabrication and electron transport in a novel heterostructure in which layers of AlGaAs and GaAs have been grown after a submicron free-standing GaAs wire has been formed. Electronic conduction at low temperatures in this material is shown to be consistent with three-dimensional hopping conduction with a transition to one-dimensional hopping at temperatures below 1 K.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.109287
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  • 10
    Electronic Resource
    Electronic Resource
    Back-gated split-gate transistor: A one-dimensional ballistic channel with variable Fermi energy (1992)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 60 (1992), S. 2782-2784 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We have studied the quantized conductance of a one-dimensional ballistic channel in the two-dimensional electron gas of a back-gated GaAs/AlGaAs heterostructure. A standard Schottky split-gate fabricated with electron-beam lithography techniques is used to define the one-dimensional channel, but we incorporate an epitaxially grown in situ back-gate, situated ∼1 μm below the electron gas, to provide additional control of the carrier density. Quantized conductance steps can be induced by changing the bias on either gate, highlighting the self-consistent nature of the electrostatics involved. We show that we can, in principle, achieve independent control of the one-dimensional carrier density and channel width.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.106849
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