نتایج جستجو برای: impact ionization

تعداد نتایج: 796390  

2002
R. Moshammer H. Kollmus S. Hagmann M. Schulz R. Mann B. Feuerstein A. Dorn D. Fischer C. Höhr C. D. Schroeter J. R. Crespo Lopez-Urrutia R. E. Olson J. Ullrich

After many years of intense research the dynamical response of quantum-mechanical many-particle systems perturbed by an external time dependent force still remains as one the most fundamental and challenging problems in physics. Among them the three-body Coulomb problem represents the most prominent example. It can be studied in great detail in atomic collisions and ionization of simple atoms b...

Journal: :Physical review letters 1996
Schappe Walker Anderson Lin

We present a new method for measuring absolute total electron-impact ionization cross sections. The technique measures fractional loss rates from a magneto-optical trap due to electron-impact ionization. The method requires only relative measurements of the number of target atoms and therefore eliminates a major source of difficulty in previous experiments. We report total ionization cross sect...

Journal: :Physical review letters 2000
Sidky Illescas Lin

Full three-dimensional ejected electron momentum distributions for proton impact ionization of atomic hydrogen are calculated for impact energies 10 through 50 keV. The distributions show a peak in the longitudinal momentum at half the projectile impact velocity: the v/2 peak. A quantitative assessment of saddle point ionization, based on quantum and classical analysis, reveals that the v/2 pea...

2015
K. Ullah S. Riaz M. Habib F. Abbas S. Naseem I. Shah A. Bukhtiar

Impact ionization in fully depleted (FD) Silicon On Insulator (SOI) n-Channel MOSFET is investigated as a function of the doping concentration. We have found that impact ionization increases with the decrease in the doping concentration and vice versa. Simulation results obtained from Sentaurus TCAD with the higher doping concentration can control the threshold voltage (Vth). Furthermore we hav...

Journal: :SIAM Journal of Applied Mathematics 2008
Manuel Arrayás Santiago Betelú Marco Antonio Fontelos José L. Trueba

In this paper we describe the formation of fingers from ionization fronts for a hydrodynamic plasma model. The fingers result from a balance between the destabilizing effect of impact ionization and the stabilizing effect of electron diffusion on ionization fronts. We show that electron diffusion acts as an effective surface tension on moving fronts and estimate analytically the size of the fin...

2012
Winifred M. Huo

In a partially ionized hypersonic flow field, electron collision plays a significant role in energy re-distribution and in the production of excited states of atoms and molecules that can subsequently radiate. Thus electron collision data is part of the database used in modelling high speed entry flows. First principles computational methods for the calculation of electron-impact data are revie...

2011
L. Meng D. N. Ruzic

Modulated pulse power MPP technology is a derivative of high power pulsed magnetron sputtering that allows unprecedented user control over the growth process, although the critical time-dependent plasma properties during the power pulse have not been studied until now. Using a MPP plasma generator, pulses of custom voltage waveforms were generated and applied to the cathode of a 36 cm diameter ...

2004
B. K. Ng J. P. R. David D. J. Massey R. C. Tozer G. J. Rees F. Yan J. H. Zhao M. Weiner

The measured photomultiplication and excess noise characteristics of two 4H-SiC p-i-n diodes, with i-region widths of 0.105 μm and 0.285 μm, were modelled using a nonlocal multiplication model to determine the ionization threshold energies and the impact ionization coefficients of 4H-SiC. The modelled ionization coefficients accurately predicted the breakdown voltage of a 0.485 μm p-i-n structu...

2003
I. Bray K. Bartschat A. T. Stelbovics

We present an implementation of the convergent close-coupling ~CCC! method, in which the Laguerre-based target states are replaced with box-based eigenstates. Discrete energies are obtained by taking the states that vanish at the box radius R0, with convergence being established by simply varying R0. Excellent agreement between boxand Laguerre-based CCC, exterior complex scaling, and renormaliz...

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