Electron Microscopy of Nanoledges at the (001)InAs/(001)GaAs Interface for an Approximate Orientation Relationship

Abstract

The structure of the InAs/GaAs(001) epitaxial heterointerface is observed by high resolution electron microscopy (HREM) along [110] when there is a slight long range angular misorientation between the two crystals around the common observation direction. The lattice misfit and the local misorientation (η = 6.9%, Δθ = 1.5°) are simultaneously accommodated via a non planar and non pseudoperiodic distribution of defects involving usual 90° and 60° dislocation cores and yet unreported nanoledges with exotic Burgers vector contents. One of these nanoledges is five (001) planes high and has a total Burgers vector content equal to (1/6)[33‐1]. Its local elastic field has been analysed in terms of ribbon‐like Somigliana dislocations. It depends on η, Δθ and its nanoledge height. Comparisons between the experimental and calculated tunnel positions between atom columns are given to appreciate the validity of the model.

Atomic scale observation of the displacement fields generated by the intrinsic defects of {111}Ni 3 Al/(010)Ni 3 Nb close-packed interfaces

“…For example, a continuous distribution of dislocations accommodating the disregistry of the crystals along TE and a modi® cation of the positions of the singularity cores are sometimes required for large ledge heights (Ben Youssef et al 1999). For example, a continuous distribution of dislocations accommodating the disregistry of the crystals along TE and a modi® cation of the positions of the singularity cores are sometimes required for large ledge heights (Ben Youssef et al 1999).…”