GaAs/Ge/GaAs Sublattice Reversal Epitaxy on GaAs (100) and (111) Substrates for Nonlinear Optical Devices

Sublattice reversal epitaxy is demonstrated in lattice-matched GaAs/Ge/GaAs (100) and (111) systems using molecular beam epitaxy, and confirmed by reflection high energy electron diffraction and preferential etching. In the GaAs/Ge/GaAs (100) system, the sublattice reversal is assisted by self-annihilation of the antiphase domains generated at the GaAs/Ge interface. In the GaAs/Ge/GaAs (111) system, the sublattice reversal results from the unique structure of the As-terminated Ge (111) surfaces. The quality of the sublattice-reversed GaAs crystal is investigated using cross-sectional transmission electron microscopy. A method to fabricate a periodically domain-inverted structure using sublattice reversal epitaxy is demonstrated for the GaAs/Ge/GaAs (100) system.