Nucleation and growth of GaAs on Ge and the structure of antiphase boundaries.

Using a UHV scanning transmission electron microscope equipped with a molecular beam epitaxy chamber, the formation of the GaAs/Ge interface produced by deposition of GaAs on Ge substrate thin films with (111) or (110) or (100) orientations has been investigated. Three dimensional nucleation and growth of facetted GaAs epitaxial islands are characteristic of this interface. The formation and orientation of antiphase boundaries with GaAs films are obtained from the structure analysis of these ultra thin films.