Asymmetric recombination region

A two-dimensional simulation has also been performed of the accumulation of defects with an asymmetric recombination region [113] chosen in the form of a rectangle with vp = a x b. The anisotropic case in which the... 

It is convenient to consider a model of an anisotropic recombination region the reflecting recombination sphere (white sphere) with black reaction spots on its surface [77, 78], The measure of the reaction anisotropy here is the geometrical steric factor Q which is a ratio of a black spot square to a total surface square. Such a model could be actual for reactions of complex biologically active molecules and tunnelling recombination when the donor electron has an asymmetric (e.g., p-like) wavefunction. Note the non-trivial result that at small Q, due to the partial averaging of the reaction anisotropy by rotational motion arising due to numerous repeated contacts of reactants before the reaction, the reaction rate is K() oc J 1/2 rather than the intuitive estimate Kq oc Q. 

In the NI case most of the starts are from inside the recombination zone, while in the IN region ions always start from outside. In the latter case Zo is a bit smaller than z, but the difference is insignificant and the free-energy dependence of Zo results mainly from the z(AGr) dependence. According to the EM equations (3.194) and (3.207), z should reproduce the PEG law peculiar to Wr(ct). This is the symmetric curve represented by the dotted line in Figure 3.37, while the true kinetic efficiency represented by the thick solid line in the same figure is asymmetric and wider. This is due to the X(r) dependence, which broadens the PEG law for recombination as it did for ionization [compare the dashed and solid lines (a) in Fig. 3.16], This dependence is accounted for when z is calculated from the integral (3.337). 

Choo. Carrier generation-recombination in the space charge region of an asymmetrical p-n junction... 

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