Atomistic processes of surface segregation during Si-Ge MBE growth

摘要

Atomic-scale segregation at step edges during growth is proposed as the origin of ordering in the Si-Ge system. Cross-sectional Z-contrast imaging of as-grown structures reveals that a variety of ordered phase variants can exist at Si on Ge interfaces as a result of vertical segregation during superlattice growth. Long-range ordering in alloys is predicted to arise due to segregation at monolayer or bilayer steps depending on the evolving surface morphology.