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(a) Schematic and (b) TEM image of a cross section of the FACELO-grown sample, viewed along the direction of stripes (shaded dark). The white triangles indicate schematically the growth mode of the seed columns.
TEM images of boundaries A and B tilted by about the stripe axis. Careful examination shows that the same dislocations in the central boundary B are visible in both images, consistent with a Burgers vector of ; dislocations in boundaries A, which are of the same type, but opposite in sign, show unequal contrast in the two images owing to grain rotations.
Schematic showing how crystal planes are affected by (a) a rigid body rotation associated with the out-of-plane component of , and (b) residual stress associated with the in-plane component of . The rotations are in the same sense for the horizontal (0002) planes and in the opposite sense for the vertical planes.
(a) and (b) Magnified images of the interface taken in two-beam diffracting conditions with and , respectively, showing examples (arrowed) where misfit dislocations turn over to become threading dislocations in the layer. In both cases, the boundary is oriented approximately as in Fig. 2 (right side boundary A) with the layer on the left, and the sample tilted nearly from the projection about the axes shown; (c) and (d) show schematically how the growth under stress of preexisting dislocations, or half-loops, could account for these observations.
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