1/f Noise in doped and undoped amorphous silicon

Johanson, Robert E.; Güneş, Mehmet; Kasap, S. O.

doi:10.1016/s0022-3093(99)00832-7

Cited by 9 publications

(5 citation statements)

References 16 publications

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“…Our results may be thus used as a valid guideline to analyze decoherence phenomena in Josephson circuits subject to noise stemming from fluctuating background charges and flux [64][65][66][67]. Other systems where the noise is non-Gaussian and comes from a collection of two-level fluctuators include silicon [68] and magnetic ones [69], as well as vortex matter [70].…”

Section: Introductionmentioning

confidence: 99%

Dynamics of quantum correlations in colored-noise environments

et al. 2013

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We address the dynamics of entanglement and quantum discord for two noninteracting qubits initially prepared\ud in a maximally entangled state and then subjected to a classical colored noise, i.e., coupled with an external\ud environment characterized by a noise spectrum of the form 1/f α.More specifically, we address systems in which\ud the Gaussian approximation fails, i.e., mere knowledge of the spectrum is not enough to determine the dynamics\ud of quantum correlations. We thus investigate the dynamics for two different configurations of the environment:\ud in the first case, the noise spectrum is due to the interaction of each qubit with a single bistable fluctuator with\ud an undetermined switching rate, whereas in the second case we consider a collection of classical fluctuators with\ud fixed switching rates. In both cases, we found analytical expressions for the time dependence of entanglement\ud and quantum discord, which may also be extended to a collection of fluctuators with random switching rates.\ud The environmental noise is introduced by means of stochastic time-dependent terms in the Hamiltonian, and this\ud allows us to describe the effects of both separate and common environments. We show that the non-Gaussian\ud character of the noise may lead to significant effects, e.g., environments with the same power spectrum, but\ud different configurations give rise to the opposite behavior for quantum correlations. In particular, depending\ud on the characteristics of the environmental noise considered, both entanglement and discord display either a\ud monotonic decay or the phenomena of sudden death and revivals. Our results show that the microscopic structure\ud of the environment, in addition to its noise spectrum, is relevant for the dynamics of quantum correlations and\ud may be a valid starting point for the engineering of non-Gaussian colored environments

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Section: Introductionmentioning

confidence: 99%

Dynamics of quantum correlations in colored-noise environments

et al. 2013

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“…In particular, some studies of n-type a-Si:H report unexpected phenomena for 1=f a noise such as non-Gaussian statistics and a non-linear dependence on the bias current [4,5,7]. Due to the high resistance of undoped a-Si:H, most noise measurements have involved either n-type [4][5][6][7]11] or p-type material [12,13] and then mostly with a coplanar geometry. Undoped films have been studied using either a transverse geometry or a coplanar geometry at elevated temperatures.…”

Section: Introductionmentioning

confidence: 99%

Conductance fluctuations in undoped hydrogenated amorphous silicon–germanium alloy thin films

Güneş

Johanson

Kasap

et al. 2002

Journal of Non-Crystalline Solids

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We report coplanar conductance fluctuations of device quality, undoped hydrogenated amorphous silicon-germanium alloy thin films (a-SiGe:H) measured from 430 to 490 K. The a-SiGe:H alloys produce noise power spectra similar to coplanar undoped a-Si:H films in the same temperature range. The noise power spectrum S n does not fit a single 1=f a power law but rather has two distinct regions, each accurately fitted by a power law, but with different slopes. The low frequency slope a 1 is similar to that observed in undoped a-Si:H films varying from 1.30 to 1.46 for different Ge concentrations and shows a slight temperature dependence. At higher frequencies, the slope a 2 is less than unity and temperature independent but depends on the Ge content of the film. a 2 decreases from 0.60 for no Ge (pure a-Si:H) to 0.15 for 40 at.% Ge. The noise power at lower frequencies increases and at higher frequencies decreases substantially as the temperature increases from 430 to 490 K. We infer that similar noise mechanisms are operating in undoped a-SiGe:H and a-Si:H films but that the Ge content is influencing the noise, particularly the slope at higher frequencies. In addition, the noise has the expected quadratic dependence on bias current and obeys Gaussian statistics.

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“…Despite the effect of screening, our electrometer is still sensitive to very small charge fluctuations in the a-Si:H, even at room temperature. An intriguing demonstration of this is the sensitivity of the MOSFET to telegraph noise switches in the a-Si:H. 1/ f noise and discrete telegraph switches have been observed previously in the resistance of macroscopic a-Si:H samples . The discrete switching that is sometimes observed occurs for samples where the conductance is dominated by filaments small enough to be affected by a single switch.…”

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confidence: 59%

The Effect of Electrostatic Screening on a Nanometer Scale Electrometer

2010

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We investigate the effect of electrostatic screening on a nanoscale silicon MOSFET electrometer. We find that screening by the lightly doped p-type substrate, on which the MOSFET is fabricated, significantly affects the sensitivity of the device. We are able to tune the rate and magnitude of the screening effect by varying the temperature and the voltages applied to the device, respectively. We show that despite this screening effect, the electrometer is still very sensitive to its electrostatic environment, even at room temperature.

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1/f Noise in doped and undoped amorphous silicon

Cited by 9 publications

References 16 publications

Dynamics of quantum correlations in colored-noise environments

Dynamics of quantum correlations in colored-noise environments

Conductance fluctuations in undoped hydrogenated amorphous silicon–germanium alloy thin films

The Effect of Electrostatic Screening on a Nanometer Scale Electrometer

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