Atomic Structure of Heteroepitaxial Interface between II-VI and III-V Semiconductor

A series of pseudomorphic (100) ZnSe/GaAs heterostructures were grown by molecular beam epitaxy on GaAs epilayers which had different As coverages of surfaces. A large variation of the interface state density was observed among the heterostructures by capacitance-voltage measurements. Transmission electron microscope observations of cross-sectional samples have revealed existence of an interface layer in the heterostructures grown on As-deficient GaAs surfaces. Analyses of dark field images and high resolution microscope images have shown that the interface layer has a structure similar to that of Ga₂Se₃ which crystallizes in a zincblende type structure with vacancies on the Ga sublattice.