Current-voltage behavior

Varistors. Varistors are devices that exhibit nonlinear current—voltage behavior. At low voltages, current flow is minimal and the device behaves as an ohmic insulator. As the voltage approaches a critical value, the breakdown field (Fgj ), current flow increases and the device becomes highly... 

We note that the presence of a chemical species, if it affects the double layer, can cause an increase or decrease in the barrier height 4>b in the semiconductor depending on the interaction between the species and the C-S structure. Those species that cause the barrier to increase would enhance rectifying current-voltage behavior in the C-S structure those species that cause the barrier to decrease would enhance ohmic (lack of rectification) current-voltage behavior in the C-S structure. 

However, it is important to note that, since the seminal publication of Aviram and Rattner [75], there have been attempts to demonstrate that suitably designed organic semiconductors deposited in a layer between two electrodes would give current voltage behavior analogous to the behavior of a p-n junction, even when Schottky barrier or tunnelling effects due to the metal electrodes are not important. There is a class of small molecular... 

Activation overpotential may become important with a number of electrocatalysts however, as Debenedetti and Vayenas (15) have discussed, the actual current-voltage behavior of the unit at moderate and high current densities can be well approximated by subtracting the activation overpotential from E For CO... 

If the polarization curve is obtained under conditions of constant current (galvanostatlcally) curves such as AFGE or AFDE are usually obcained and it is found that the current-voltage behavior is more time dependent. In many cases periodic fluctuations occur (34,78). Since the potential is a multivalued function of the current, this behavior is readily understandable. 

Current-voltage Behavior of a Semiconductor/metal Junction... 

Figure 11.6 shows the current-voltage behavior during the electropolishing of copper in a 13.3 M phosphoric acid + 17.7 M water solution with an electrode rotation speed of 240 rpm [20]. 

Figure 23. (A) Schematic configuration of a biofuel cell employing glucose and H2O2 as fuel and oxidizer, and using PQQ-FAD/reconstituted GOx and MP-11-functionalized electrodes as bio-catalytic anode and cathode, respectively. (B) Current-voltage behavior of the biofuel cell at different external loads. Inset electrical power extracted from the biofuel cell at different external loads.

The nonlinear current-voltage behavior associated with an electrochemical system is illustrated in Figiue 5.4(a). In the case shown here, the anodic (positive) current has an exponential dependence on potential whereas, the cathodic (negative) cvur-rent displays an influence of mass-transfer limitations. Regions are identified for which the current has a value equal to zero, the current is controlled by reaction kinetics, and the current is controlled by mass transfer. 

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