Threshold trapping

Figure 17 shows the ratio of the threshold trapping electric potential differences for the Bosch and HF channels obtained from the calculations along with the experimental values obtained for a number of different particle types. The calculated value of 0.46 is in reasonable agreement with that measured for spores, but die values for the other types of particles are much larger. 

One possible explanation for this difference between the experimental and theoretical values for the ratio of threshold trapping potentials is the presence of particle-particle interactions that may perturb the electric field gradient present between the posts. The local perturbation to the field created by one particle may amplify the dielectrophoretic force acting on a nearby particle. A large number of such interactions may cascade, resulting in a significant enhancement of the dielectrophoretic force. This could result in direct contact between particles and van der Waals forces would then act to keep the particle ensemble together. 

Figure 17, The ratio of the threshold trapping electric potential differences for the Bosch and HF channels as obtained from the calculations and as measured for several different types of particles.

Two examples of path-dependent micromechanical effects are models of Swegle and Grady [13] for thermal trapping in shear bands and Follansbee and Kocks [14] for path-dependent evolution of the mechanical threshold stress in copper. 

The effect of traps on charge carrier motion does not become noticeable until the trap concentration reaches a threshold value. One can define a critical concentration Ci/2 at which the mobility has decreased to one half of the value of the trap-free system. Eq. (12.19) predicts that. ... 

Nanocrystals are receiving significant attention for nano-electronics application for the development of future nonvolatile, high density and low power memory devices [1-3]. In nanocrystal complementary metal oxide semiconductor (CMOS) memories, an isolated semiconductor island of nanometer size is coupled to the channel of a MOS field effect transistor (MOSFET) so that the charge trapped in the island modulates the threshold voltage of the transistor (Fig. 1). 

Cross-sections for reactive scattering may exhibit a structure due to resonance or to other dynamical effects such as interference or threshold phenomenon. It is useful to have techniques that can identify resonance behavior in a system and distinguish it from other sorts of dynamics. Since resonance is associated with dynamical trapping, the concept of the collision time delay proves quite useful in this regard. Of course since collision time delay for chemical reactions is typically in the sub-picosecond domain, this approach is, at present, only useful in analyzing theoretical scattering results. Nevertheless, time delay is a valuable tool for the theoretical identification of reactive resonances. 

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