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- Vincent, Jonathan, et al.
(författare)
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Theory of a room-temperature silicon quantum dot transitor as a sensitive electrometer
- 2004
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Ingår i: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 95, s. 323-
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Tidskriftsartikel (refereegranskat)abstract
- We consider theoretically the use of a room-temperature silicon quantum dot based device for electrometer applications. The low power device includes two split gates that quantize the electronic energy levels in the emitter and collector regions. The base consists of a silicon quantum dot buried in silicon dioxide. The small size of the dot and quantization of the states in the leads combined to allow the device to operate at room temperature. The nonlinear current–voltage characteristics can be significantly altered by small changes to the potential of the split gates. Power dissipation in the device therefore changes with the split gate voltage, and this can be exploited in electrometer applications. A simple model of the power dissipated when the device is part of a microwave resonant inductor-resistor-capacitor tank circuit suggests that large changes in device power can be achieved by changing the gate voltage, thereby forming a measurable signal. We also demonstrate that the power dissipation in the device changes as the base width is varied, and that the current through the device increases exponentially with a decrease in base width.
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| 2. |
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| 3. |
- Mitsugi, F., et al.
(författare)
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Ferroelectric and colossal magnetoresistive properties of a PbZr1-xTixO3/La1-xSrxMnO3 heterostructure film
- 2000
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Ingår i: Japanese Journal of Applied Physics. - 0021-4922 .- 1347-4065. ; 39:9B, s. 5418-5420
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Tidskriftsartikel (refereegranskat)abstract
- We report the ferroelectric and magnetoresistive properties and crystallization of a PbZr0.52Ti0.48O3 (PZT)/La0.8Sr0.2MnO3 (LSMO) heterostructure film prepared by pulsed-laser deposition on a MgO(100) single crystal substrate. Ferroelectric properties such as the hysteresis loop and dielectric constant of the Au/PZT/LSMO capacitor were compared with those of the Au/PZT/YBa2Cu3O7-x, (YBCO) superconductor heterostructure film. The resistivity of the LSMO film was as low as that of the YBCO film at room temperature. The fabricated Au/PZT/LSMO capacitor had a remanent polarization of 29 muC/cm(2), a coercive field of 30 kV/cm and a dielectric constant of about 1000.
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| 4. |
- Narayan, V., et al.
(författare)
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Calculation of the temperature dependence of hot electron scattering in heavily p-doped GaAs using a high-temperature approximation to the dielectric function
- 2002
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Ingår i: Physica. B, Condensed matter. - 0921-4526 .- 1873-2135. ; 324:1-4, s. 393-402
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Tidskriftsartikel (refereegranskat)abstract
- Using a high-temperature approximation to the dielectric function within the random phase approximation, we calculate hot electron scattering rates, as a function of temperature and doping density, in p-doped GaAs. The dielectric function of the holes contains contributions from intraband excitations and interband excitations. The former reduces to an analytic form within the two pole approximation (which used Boltzmann statistics), whereas the latter was calculated numerically. The collective excitation mode of the holes was defined by intraband excitations, since at very small wavevectors, the interband excitations vanish. However, at low temperature the interband excitations were found to be the dominant Landau damping mechanism, which strongly suppressed the plasmon at moderate doping levels. At high temperature the excitations from the heavy to light band were partially suppressed, and the plasmon was not overwhelmingly Landau damped by either interband or intraband excitations. At room temperature, an analytic dielectric function where the interband excitations have been neglected, may be used to accurately calculate hot electron mean free paths. This approximation was found to become more accurate with lower doping levels, but was not appropriate at low temperature. © 2002 Elsevier Science B.V. All rights reserved.
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