Polarity of small {111}GaAs domains on (100)Sc0.32Er0.68As formed during molecular-beam epitaxial growth

Abstract

Molecular-beam epitaxial growth of GaAs on (100)ScxEr1−xAs can result in domains of various orientations. Most of the GaAs domains are of the epitaxial (100) or the twin related (221) orientation. A {111} orientation is also common. We have studied the orientational relationships of these domains by transmission electron microscopy. The polarity of small {111}GaAs domains on (100)ScErAs have been determined by electron channeling. We observe that the polarity is such that the GaAs [1̄1̄1̄] direction (as opposed to the [111] one) points outward from the original ScxEr1−xAs(100) surface. We use this observation in discussing possible models of the interface between ScErAs and GaAs.

Crystal Polarity Determination by Electron Channeling

“…By this approach, we arrive at the same current density as by two-beam Bloch wave considerations when we include the interference term between the Bloch waves 6 . For electrons the current density now becomes I(x,z) = l-sin27rfy (1) -y ( 2 ) )zsin2^x…”