Atomic structure of (110) anti-phase boundaries in GaP on Si(001)

High quality III/V-layers grown on Si enable a variety of optoelectronic devices. The performance of such devices is limited by anti-phase domains forming at monoatomic steps on the Si-surface. To date the atomic structure of anti-phase boundaries, which affects the charge distribution at polar interfaces, is unknown. Here, we use CS-corrected scanning transmission electron microscopy to reveal the atomic structure of the anti-phase boundaries in III/V-semiconductors, choosing GaP as a model system. We observe boundaries on (110) lattice planes which are atomically abrupt and also facetted ones, which introduces locally charged regions influencing device performance.