  Comprehensive investigations on ZnSe/GaAs and GaAs/ZnSe interfaces were
carried out by photoluminescence (PL) and transmission electron microscopy
(TEM), as a part of realizing high quality ZnSe-GaAs (100) hetero-valent
structures (HS). The nature of ZnSe/GaAs interface under different surface
terminations of GaAs was examined. The ZnSe/Ga-terminated GaAs was found to
have a superior optical and microstructural quality, with a chemical interface
consisting of a mixture of both the GaAs and ZnSe atomic constituents. For
GaAs/ZnSe interface studies, a low-temperature migration enhanced epitaxy
(LT-MEE) growth technique was used to grow GaAs layers under the conditions
compatible to the growth of ZnSe. Both Ga and As-initialized LT-MEE GaAs/ZnSe
interfaces were investigated. A defective transition layer was observed along
the As-initialized GaAs/ZnSe interface, which may be attributed to the
formation Zn$_3$As$_2$ compound. The correlation between the observed optical
as well as structural properties of both the (GaAs/ZnSe and ZnSe/GaAs)
interfaces and the growth conditions used in this study are discussed in
detail. This study could provide a valuable insight on the interface nature of
ZnSe-GaAs HS.
