Influence of growth parameters on the properties of ZnSe-GaAs(001) heterostructures

ZnSe-GaAs(001) heterostructures were fabricated by molecular beam epitaxy at 290°C employing different Zn/Se flux ratios. Se-rich growth conditions resulted in a Se-rich interface composition and lower valence band offsets (as low as 0.6 eV). Zn-rich conditions yielded a Zn-rich interface composition, and higher valence band offsets (as high as 1.2 eV). Improved optical properties of the ZnSe overlayers were achieved by employing non-stoichiometric growth conditions only in the early stages of growth (∼ 2 nm).