The Experts below are selected from a list of 270 Experts worldwide ranked by ideXlab platform
Amnon Aharony - One of the best experts on this subject based on the ideXlab platform.
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Noise Spectra of an interacting quantum dot
Physical Review B, 2011Co-Authors: N Gabdank, E A Rothstein, O Entinwohlman, Amnon AharonyAbstract:We study the Noise Spectra of a many-level quantum dot coupled to two electron reservoirs, when interactions are taken into account only on the dot within the Hartree-Fock approximation. The dependence of the Noise Spectra on the interaction strength, the coupling to the leads, and the chemical potential is derived. For zero bias and zero temperature, we find that as a function of the (external) frequency, the Noise exhibits steps and dips at frequencies reflecting the internal structure of the energy levels on the dot. Modifications due to a finite bias and finite temperatures are investigated for a non-interacting two-level dot. Possible relations to experiments are pointed out.
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Noise Spectra of a biased quantum dot
Physical Review B, 2009Co-Authors: E A Rothstein, O Entinwohlman, Amnon AharonyAbstract:The Noise Spectra associated with correlations of the current through a single level quantum dot, and with the charge fluctuations on the dot, are calculated for a finite bias voltage. The results turn out to be sensitive to the asymmetry of the dot's coupling to the two leads. At zero temperature, both Spectra exhibit two or four steps (as a function of the frequency), depending on whether the resonant level lies outside or within the range between the chemical potentials on the two leads. In addition, the low-frequency shot Noise exhibits dips in the charge Noise, and dips, peaks, and discontinuities in the derivative of the current Noise. In spite of some smearing, several of these features persist at finite temperatures, where a peak can also turn into a dip.
H Eleuch - One of the best experts on this subject based on the ideXlab platform.
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dynamics in terahertz semiconductor microcavity quantum Noise Spectra
Journal of Optics, 2018Co-Authors: H Jabri, H EleuchAbstract:We investigate the physics of an optical semiconductor microcavity containing a coupled double quantum well interacting with cavity photons. The photon statistics of the transmitted light by the cavity is explored. We show that the nonlinear interactions in the direct and indirect excitonic modes generate an important squeezing despite the weak nonlinearities. When the strong coupling regime is achieved, the Noise Spectra of the system is dominated by the indirect exciton distribution. At the opposite, in the weak regime, direct excitons contribute much larger in the Noise Spectra.
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Noise Spectra of microcavity emitting field in the linear regime
European Physical Journal D, 2008Co-Authors: H EleuchAbstract:Our work presents a theoretical study on the behavior of the fluctuation statistics of the field emitted from a semiconductor microcavity containing a quantum well. We derive an analytical expression of the Noise Spectra in non-resonant pumping. Dynamical behaviors of the Noise Spectra depending on the thermal bath and the detuning between exciton and cavity frequencies are discussed.
O Entinwohlman - One of the best experts on this subject based on the ideXlab platform.
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Noise Spectra of an interacting quantum dot
Physical Review B, 2011Co-Authors: N Gabdank, E A Rothstein, O Entinwohlman, Amnon AharonyAbstract:We study the Noise Spectra of a many-level quantum dot coupled to two electron reservoirs, when interactions are taken into account only on the dot within the Hartree-Fock approximation. The dependence of the Noise Spectra on the interaction strength, the coupling to the leads, and the chemical potential is derived. For zero bias and zero temperature, we find that as a function of the (external) frequency, the Noise exhibits steps and dips at frequencies reflecting the internal structure of the energy levels on the dot. Modifications due to a finite bias and finite temperatures are investigated for a non-interacting two-level dot. Possible relations to experiments are pointed out.
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Noise Spectra of a biased quantum dot
Physical Review B, 2009Co-Authors: E A Rothstein, O Entinwohlman, Amnon AharonyAbstract:The Noise Spectra associated with correlations of the current through a single level quantum dot, and with the charge fluctuations on the dot, are calculated for a finite bias voltage. The results turn out to be sensitive to the asymmetry of the dot's coupling to the two leads. At zero temperature, both Spectra exhibit two or four steps (as a function of the frequency), depending on whether the resonant level lies outside or within the range between the chemical potentials on the two leads. In addition, the low-frequency shot Noise exhibits dips in the charge Noise, and dips, peaks, and discontinuities in the derivative of the current Noise. In spite of some smearing, several of these features persist at finite temperatures, where a peak can also turn into a dip.
R.m. Gray - One of the best experts on this subject based on the ideXlab platform.
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Quantization Noise Spectra
IEEE Transactions on Information Theory, 1990Co-Authors: R.m. GrayAbstract:Several results describing the behavior of quantization Noise in a unified and simplified manner are discussed. Exact formulas for quantizer Noise Spectra are developed. They are applied to a variety of systems and inputs, including scalar quantization (PCM), dithered PCM, sigma-delta modulation, dithered sigma-delta modulation, two-stage sigma-delta modulation, and second-order sigma-delta modulation.
Tomas Gonzalez - One of the best experts on this subject based on the ideXlab platform.
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Analysis of Noise Spectra in GaAs and GaN Schottky barrier diodes
Semiconductor Science and Technology, 2011Co-Authors: D. Pardo, Susana Perez, Jesus Grajal, B. Mencía, Javier Mateos, Tomas GonzalezAbstract:The Monte Carlo method is applied in this paper to characterize the Noise Spectra of GaAs and GaN Schottky barrier diodes operating under static and time varying conditions. We show the influence of the structure of the diode and working regimes on the Noise spectrum of the diodes. Besides, the paper evaluates the capabilities of published analytical models to describe the Noise Spectra in Schottky diodes under time varying conditions. This is a further step toward the development of a design tool that integrates both the electrical response and the intrinsic Noise generated in the devices.
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TeraHertz Emission and Noise Spectra in HEMTs
AIP Conference Proceedings, 2005Co-Authors: J. Mateos, Susana Perez, D. Pardo, Tomas Gonzalez, Jerzy Łusakowski, Nina Dyakonova, W. Knap, Sylvain Bollaert, Yannick Roelens, A. CappyAbstract:In this work we investigate, by means of Monte Carlo simulations, the physics of the recently observed emission of THz radiation at low temperature (4.2 K) from InGaAs/InAlAs lattice‐matched high electron mobility transistors, HEMTs. The spectrum of the emitted signal consists of two maxima; the one at lower frequency (around 1 THz) is sensitive to UDS and UGS, while the higher frequency peak (around 5 THz) is not. The gate current Noise Spectra obtained with room‐temperature Monte Carlo simulations of similar HEMTs also show those features, although some quantitative discrepancies arise from the different temperature conditions. The signature of plasma oscillations is known to appear in the current Noise spectrum, producing peaks appearing at very high frequencies. On the other hand, peaks at frequencies around 1 THz can be associated with the formation of Gunn domains within the transistors. Therefore, the analysis of the Noise Spectra of these devices can provide useful information that can help to und...
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TeraHertz Emission From Nanometric HEMTs Analyzed by Noise Spectra
AIP Conference Proceedings, 2005Co-Authors: J. F. Millithaler, J. Mateos, Susana Perez, D. Pardo, Tomas Gonzalez, W. Knap, Luca Varani, Christophe Palermo, J. Lusakowski, Nina DyakonovaAbstract:TeraHertz emission from High Electron Mobility Transistors has been recently measured from experiments. The experiments show emission Spectra with two peaks in the TeraHertz range: one around 1 THz is sensitive to drain and gate voltages, and another one around 5 THz which is fixed. In order to get physical insight into the microscopic mechanism at the basis of the radiation emission we have performed a Monte Carlo simulation of the measured transistors using the current Noise Spectra as sensitive probes to detect the presence of electrical instabilities. Numerical results are found to be in good agreement with experiments confirming the presence of an oscillatory dynamics in the TeraHertz range.
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Current Noise Spectra of Schottky barrier diodes with electron traps in the active layer
Journal of Applied Physics, 2005Co-Authors: Susana Perez, Tomas GonzalezAbstract:We present a microscopic analysis of current fluctuations in a GaAs n+-n-metal Schottky barrier diode containing electron traps in the active layer. An ensemble Monte Carlo simulation is used for the calculations. We analyze the influence of generation-recombination mechanisms of electrons with traps on the current–voltage characteristics and Noise Spectra of the diode. The presence of traps reduces both the flatband voltage and the current level in the series-resistance regime. With respect to the Noise, significant modifications are observed in the current Noise Spectra. In the barrier-limited regime, while at low-frequency shot Noise is not found to change, the returning-carriers peak is strongly modulated by the influence of the traps. Beyond flatband conditions generation-recombination Noise becomes evident at low frequency, exhibiting a quadratic dependence on the current.
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Monte Carlo analysis of Noise Spectra in Schottky‐barrier diodes
Applied Physics Letters, 1993Co-Authors: Tomas Gonzalez, Luca Varani, Daniel Pardo, Lino ReggianiAbstract:We present a microscopic analysis of current fluctuations in a GaAs Schottky‐barrier diode under forward‐bias conditions. The calculations are performed by employing a one‐dimensional Poisson solver coupled self‐consistently with an ensemble Monte Carlo simulator. Results support and complement previous findings of M. Trippe, G. Bosman, and A. van der Ziel [IEEE Trans. Microwave Theory Tech. MTT‐34, 1183 (1986)] based on phenomenological models. In particular, the coupling between fluctuations in carrier velocity and self‐consistent field is found to be essential in determining the Noise Spectra as a function of applied voltages.
