Frank-Shockley partial dislocations

Figure n.n (p. 301) Polar plots of the hydrostatic pressure field of a 1 /6[2-203] Frank-Shockley partial dislocation in a-plane GaN (a) assuming the isotropic case, (b) taking anisotropy into account. 

The density of partial dislocations allows us also to estimate that the density of Ii-type BSFs is one order of magnitude larger than the density of l2-type faults. However, occasionally it is possible that two Ii faults with different Burgers vectors meet each other, resulting in the appearance of one Shockley partial dislocation instead of two Frank-Shocldey dislocations. This special case is illustrated in Figure 10.8. 

FIGURE 2 HREM image of partial dislocations and their schematic maps found in the low temperature GaN layer near the interface (a) interstitial Frank loop (the position of the extra half plane is indicated by arrows in the image) (b) isolated Frank partial dislocation (c) reaction between a dissociated edge dislocation and Shockley partial that is displaced by one basal plane (d) dislocation notation for hexagonal crystal used in (a) - (c). (From [3].)... 

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