Atomic structure of an unusual linear defect at the (001)InAs/(001)GaAs epitaxial interface

Three types of linear defects are observed by high-resolution electron microscopy along the InAs/GaAs(001) interface formed by molecular beam epitaxy deposition of InAs (300 nm) on a GaAs substrate: classical 90 degrees and 60 degrees misfit dislocations and an unusual type of linear defect that is a (1 (1) over bar 0) nanofacet extended over similar to 1 nm and bordered by a 60 degrees dislocation (1/2)[101], Extensive numerical simulations show that the total Burgers vector content of the defect, which includes the contributions of the 60 degrees dislocation and that of a dislocation distribution along the nanofacet, is very close to (1/12)[605] or (1/12)[0 (6) over bar 5], according to the sense of the screw component. A comparison between the experimental and calculated elastic displacement fields has been undertaken from image contrast simulations and the theory of dislocation distribution. Copyright (C) 2000 John Wiley & Sons, Ltd.