Search results for "Transient current"

showing 2 items of 2 documents

SOIL IONIZATION DUE TO HIGH PULSE TRANSIENT CURRENTS LEAKED BY EARTH ELECTRODES

2009

This paper proposes a numerical model of the soil ionization phenomena that can occur when earth electrodes are injected by high pulse transient currents, as the one associated with a direct lightning stroke. Based on finite difference time domain numerical scheme, this model ascribes the electrical breakdown in the soil to the process of discharge in the air. In fact, as soon as the local electric field overcomes the electrical strength, the air in the voids trapped among soil particles is ionized, and the current is conducted by ionized plasma paths locally grown. The dimension of these ionized air channels is strictly dependent upon the local temperature. Thus, a local heat balance is en…

Materials scienceFinite-difference time-domain methodElectrical breakdownPlasmaMechanicsCondensed Matter PhysicsElectronic Optical and Magnetic MaterialsPulse (physics)Settore ING-IND/31 - ElettrotecnicaSettore MAT/08 - Analisi NumericaElectric fieldIonizationTransient (oscillation)transient currentsElectrical and Electronic EngineeringCurrent (fluid)numerical modelfinite difference schemeProgress In Electromagnetics Research B
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Transient photoresponse and incident power dependence of high-efficiency germanium quantum dot photodetectors

2012

We report a systematic study of time-resolved and power-dependent photoresponse in high-efficiency germanium quantum dot photodetectors (Ge-QD PDs), with internal quantum efficiencies greater than 100 over a broad wavelength, reverse bias, and incident power range. Turn-on and turn-off response times (τ on and τ off) are shown to depend on series resistance, bias, optical power, and thickness (W QD) of the Ge-QD layer, with measured τ off values down to ∼40 ns. Two different photoconduction regimes are observed at low and high reverse bias, with a transition around -3 V. A transient current overshoot phenomenon is also observed, which depends on bias and illumination power. © 2012 American …

Materials sciencePhotoresponseReverse biaGeneral Physics and Astronomychemistry.chemical_elementPhotodetectorGermaniumOptical powerPhotoconductionTime-resolvedSettore ING-INF/01 - ElettronicaSeries resistanceOpticsElectrical resistance and conductancePhotodetectorOptical powerEquivalent series resistanceSystematic studybusiness.industryPhotoconductivityInternal quantum efficiencyQuantum-dot photodetectorPhotonWavelengthSemiconductor quantum dots GermaniumchemistryQuantum dotTransient current Electric resistanceOptoelectronicsIncident powerbusiness
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