Effects of dislocations on transport properties of two dimensional electron gas .1. Transport at zero magnetic field

This paper presents a theoretical analysis of the scattering potentials associated with dislocations in the case of two dimensional electron gas. It is shown that dislocations act mainly on the free carrier mobility through the potential associated with their linear electric charge and not with their strain field potentials. Two different experimental cases, both supported by GaAlAs-GaInAs-GaAs samples, have been considered: (i) samples containing long misfit dislocations issuing from a partial relaxation, during the crystal epitaxial growth and (ii) samples containing dislocation segments introduced by plastic deformation. It is shown that in the case of long misfit dislocations, the free carrier mobility parallel to the dislocations remains unaffected by dislocations while it is probably controlled by some tunneling effect in the direction perpendicular to the lines. In the case of dislocation segments, the free carrier mobility is controlled in both directions by a diffusion process which may be described with the help of a phenomenological potential. (C) 1996 American Institute of Physics.