Field-effect mobility, definition

Using Eq. (1) as the basic definition for field-effect mobility, it was found that in organic FETs, as in a-Si FETs, the mobility depends on the induced charge [1], The Qind dependence is experimentally observed as a gate-bias dependent mobility, because ... 

Moreover, such a description requires the definition of resolution in isotachophoresis and shows the result that can be expected from optimalization procedures. In electrophoresis the migration velocity, V, of a constituent, i, is given by the product of effective mobility, m, and the local field strength, E. 

In the zone electrophoresis method the sample is placed in a definite area of the separation column filled with the electrolyte. After the electrical field has been imposed onto the system, individual particles migrate, according to their effective mobilities with different speeds, towards the respective electrodes (and, concomitantly, both positively and negatively charged particles are separated). The constituents of the mixture are separated into distinct zones, that, however, are not sharp their width increases with the increasing separation time and, consequently, the maximum compound concentration within the zones decreases. 

When the film is short-circuited and heated to high temperatures at which the molecules attain a sufficiently high mobility, a current is observed in the external circuit. This phenomenon is called pyroelectric effect, thermally stimulated current, or, when the film has been polarized by a static field prior to measurement, depolarization current. The conventional definition of pyroelectricity is the temperature dependence of spontaneous polarization Ps, and the pyroelectric constant is defined as dPJdd (6 = temperature). In this review, however, the term will be used in a broader definition than usual. The pyroelectric current results from the motion of true charge and/or polarization charge in the film. Since the piezoelectricity of a polymer film is in some cases caused by these charges, the relation between piezoelectricity and pyroelectricity is an important clue to the origin of piezoelectricity. 

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