It was pointed out that 2 types of parallel dislocation could be introduced at the interfaces of quantum wells by means of plastic deformation (resulting in the presence of short dislocation segments), or by choosing a quantum-well thickness near to the critical value (in such a way that only one family of long misfit dislocations could develop). Magneto-transport measurements were performed at 4.2K on such samples. It was shown that dislocations introduced strongly anisotropic resistivity characteristics. The resistivity anisotropy ratio (perpendicular/parallel) attained a value of 5 in plastically deformed samples and a value of 150 in partially relaxed samples. In the first type of sample (with short dislocation segments), the results could be analyzed in terms of diffusion processes. In the second type of partially relaxed sample (containing long misfit dislocations), the conductivity perpendicular to the dislocation lines corresponded to a tunnelling process for the overcoming of dislocation barriers. In both cases, it was shown that the Coulomb potential which resulted from the dislocation linear charge was the main scattering mechanism when compared with the potentials that were associated with the dislocation strain field. When a magnetic field was applied, the dislocation potentials were responsible for an equal broadening of each Landau level.

J.L.Farvacque, Z.Bougrioua, D.Ferre: Materials Science Forum, 1995, 196-201, 549-54