Space-charge profiles

Analogously we have to proceed if we are measuring in the orthogonal direction the results will be completely different (space charge profile, core effects). Even though the overall effect can be obtained more precisely by a superposition of bulk values and interfacial excess contributions, it is more convenient for large space... 

Figure 6.16 Junction geometry, space-charge profile and potential profile for an extended junction solar cell, (a) Planar junction (b) Mildly curved junction with curvature radius larger than the space-charge width (c) Curvature radius shghtly smaller than the space-charge width (d) Curvature radius much smaller than the space-charge width.

Figure 17.3 Space charge profiles of electrons ZnO. Varying doping levels (10, 10 , and...

Eflect of Space Charge Profiles on the Observed Conductivity... 

Fig. 5.76 Enrichment, depletion and inversion effects with regard to the partial conductivities and the total conductivity. In the concentration presentation carrier (1) is enriched and the counterdefect (2) is depleted. Note too that, in the case of a mixed conductor (electronic and ionic defects) the space charge profile causes changes in the transference number (Ueon/u, < ion/o )-...

In the case of the Mott-Schottky boundary layer (majority charge carrier immobile, counterdefect depleted), we obtained a simple result for high depletion and could ap-proximate the space charge profile by means of a rectangular function of width A oc Ay l o total surface charge is approximately obtained by multiplication of A with the constant doping concentration m resulting in ... 

Another technique consists of MC measurements during potential modulation. In this case the MC change is measured synchronously with the potential change at an electrode/electrolyte interface and recorded. To a first approximation this information is equivalent to a first derivative of the just-explained MC-potential curve. However, the signals obtained will depend on the frequency of modulation, since it will influence the charge carrier profiles in the space charge layer of the semiconductor. 

Figure 9 shows the electrical potential and the space charge density profiles for concentrations c" = 1000 mM and c = 20 mM and Galvani potential difference f =... 

FIG. 9 Simulated electrical potential and space charge density profiles at the water-1,2-DCE interface polarized at/= 5 in the absence (a) and in the presence (b) of zwitterionic phospholipids. The supporting electrolyte concentrations are c° = 20 mM and c = 1000 mM. The molecular area of the phospholipids is 150 A, and the corresponding surface charge density is a = 10.7 xC/cm. The distance between the planes of charge associated with the headgroups is d = 3 A. 

FIGURE 5.6 (See color insert following page 302.) Momentum and coordinate space charge density profiles for the reaction path from HNC to HCN. 

Fig. 3 -13. (a) A ion levels at the surface and in the interior of ionic compound AB, and (b) concentration profile of lattice defects in a surface space charge layer since the energy scales of occupied and vacant ion levels are opposite to each other, ion vacancies accumulate and interstitial ions deplete in the space charge layer giving excess A ions on the surface. 

Fig ures 5-43 and 5—44 illustrate the band bending and the concentration profile of charge carriers in these four types of space charge layers. 

Fig. 6-53. Interfadal charges, electron levels and electrostatic potential profile across an electric double layer with contact adsorption of dehydrated ions on semiconductor electrodes ogc = space charge o = charge of surface states = ionic charge due to contact adsorption dsc = thickness of space charge layer da = thickness of compact la3rer.

Fig. 9-9. Potentia] profile and band bending aaoss a semiconductor electrode interface 4 = electrostatic inner potential OHh)- potential in a space charge (a compact) layer.

Figure 3.38. Principle of the photorefractive effect By photoexcitation, charges are generated that have different mobilities, (a) The holographic irradiation intensity proHle. Due to the different diffusion and migration velocity of negative and positive charge carriers, a space-charge modulation is formed, (b) The charge density proHle. The space-charge modulation creates an electric Held that is phase shifted by 7t/2. (c) The electric field profile. The refractive index modulation follows the electric field by electrooptic response, (d) The refractive index profile.

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