Charge carrier flux

The equations generally developed include all forms of the conduction. Eor example, to determine the flux or conductivity of ions in a soHd electrolyte as compared to electrons in a semiconducting ceramic, two terms are of interest the number of charge carriers and the mobiUty. The effects of temperature, composition, and stmeture on each of these terms must also be considered. 

Figure 14. PMC potential dependence, calculated from analytical formula (18) for different interfacial rate constants for minority carriers S = 1 cm, minority carrier flux toward interface I,- 1 cm-2s 1, a= 780enr1, L = 0.01 cm, 0=11.65 cmV, Ld = 2x 0"3cm), (a) sr = 0 and different charge-transfer rates (inserted in the figures in cm s 1), (b) Constant charge-transfer rate and different surface recombination rates (indicated in the figure).

In silane discharges several ions are observed to be involved in a charge exchange process, and therefore maxima in their ion energy distribution at distinct energies are observed. The charge carrier density and the plasma potential that result from the fit of the lED allow for the quantification of the related parameters sheath thickness and ion flux. This method has been be used to relate the material quality of a-Si H to the ion bombardment [301. 332] see also Section 1.6.2.3. 

The number of charge carriers generated in the SCR depends on the absorbed flux of incident photons per unit area P, the width W of the SCR and the wave-length-dependent absorption coefficient a of bulk Si. The latter parameter is shown in Fig. 7.6, while the resulting penetration depth for light of different wavelengths is shown in Fig. 10.4a. 

The following compilation is restricted to the transport coefficients of protonic charge carriers, water, and methanol. These may be represented by a 3 X 3 matrix with six independent elements if it is assumed that there is just one mechanism for the transport of each species and their couplings. However, as discussed in Sections 3.1.2.1 and 3.2.1, different types of transport occur, i.e., diffusive transport as usually observed in the solid state and additional hydrodynamic transport (viscous flow), especially at high degrees of solvation. Assuming that the total fluxes are simply the sum of diffusive and hydrodynamic components, the transport matrix may... 

We shall see, the particular surface chemistry which ultimately dominates at a particular surface in a given experiment will be greatly influenced by the flux and energy of positive charge carriers that arrive at that surface simultaneously with ground state and excited state neutral species as well as the chemical nature of the surface. 

The thermoelectric effect is due to the gradient in electrochemical potential caused by a temperature gradient in a conducting material. The Seebeck coefficient a is the constant of proportionality between the voltage and the temperature gradient which causes it when there is no current flow, and is defined as (A F/A7) as AT- 0 where A Fis the thermo-emf caused by the temperature gradient AT it is related to the entropy transported per charge carrier (a = — S /e). The Peltier coefficient n is the proportionality constant between the heat flux transported by electrons and the current density a and n are related as a = Tr/T. 

Let us discuss an L matrix transformation for isothermal and isobaric atomic fluxes when there is one additional electronic species present. We start with the flux equations in which the index j denotes the atomic species and e denotes the electric charge carriers (eg., electrons). 

The simultaneous movement of ionic and electronic charge carriers under the driving force of a gradient in the electrochemical potential of oxygen facilitates transport of oxygen in the oxide bulk. The flux density of oxide anions is given (Figure 8.12) [77-79,109] by the ambipolar diffusion equation (see Section 5.7.6) [110,111]... 

Electrolytic permeability — of ion-conducting - solid materials is the transport of neutral potentialdetermining component(s) under a -> chemical potential gradient due to the presence of bulk electronic conductivity in the material, or a parameter describing this transport. As the flux of ions is charge-compensated by a simultaneous flux of electronic charge carriers, -> steady-state permeation can be achieved without external circuitry. The transport processes can be quantitatively described in terms of -> ambipolar conductivity. 

The first equation shows that the flux of -> charge carriers in an electrochemical system is proportional to the partial conductivity and thermodynamic driving force, namely the electrochemical potential gradient (see Onsager equation). When the chemical potential of... 

Thus, even though two electrolytic conductors have the same geometry, they need not necessarily have the same specific conductivity (Fig. 4.52 and Table 4.8) the number of charge carriers in that normalized geometry may be different, in which case their fluxes under an applied electric field will be different. Since the specific conductivity of an electrolytic solution varies as the concentration, one can write... 

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