Structural and electronic properties of ZnSe/AlAs heterostructures

Pseudomorphic ZnSe/AlAs(001) heterostructures were fabricated by molecular beam epitaxy on GaAs wafers. Intrinsic stacking faults on (111) planes originating at the II-VI/III-V interface and propagating throughout the II-VI overlayer were the main type of native defects observed. The interface termination was varied by adsorption of Zn or Se onto the AlAs(001)3 × 1 surface prior to ZnSe growth. The resulting large changes in interface composition and band discontinuities mirror those obtained by employing Zn- or Se-rich growth conditions in the early stages of heterojunction fabrication. Band offsets calculated from first principles for ZnSe/GaAs, when rescaled by the different magnitude of the electrostatic interface dipole, yield a range of predictions in good agreement with experiment for ZnSe/AlAs.