Ion Channeling in Elastically Strained Superlattices

Abstract

ABSTRACTA review is given of the channeling behavior observed in superlattice materials. Elastic strains within the layers have been shown to be the source of the unusual ion dechanneling observed originally in InAs/GaSb and since observed in several other semiconductor superlattices. These strains occur because of the slight mismatch between the lattice constants of the two materials and cause the rows and planes of atoms in the crystal that are inclined to the surface normal to have small directional misalignments at the interfaces between the layers. The effects of these misalignments have been studied by computer simulations of ion trajectories in the crystal and shown to account in a reasonable manner for the observed dechanneling behavior. Calculations have been done as a function of the amount of misalignment to give an indication of how much dechanneling might be expected in other superlattices formed of any pair of materials that have slight mismatches. Various ways of measuring the amount of misalignment have also been studied by simulations and experiments.