MnS/ZnSe on GaAs grown by molecular beam epitaxy

Zinc-blende MnS/ZnSe heterostructures on GaAs(100) have been characterized by X-ray photoelectron spectroscopy (XPS), optical methods, and transmission electron microscopy (TEM). XPS spectra indicated that the MnS/ZnSe interface is sharp and that the layers are of proper stoichiometry. TEM revealed isolated {111} stacking faults but confirmed the overall high crystalline quality and coherence of the MnS/ZnSe interface. XPS suggests a small valence band discontinuity (Delta E(v)) of about 140 meV with a type IIA alignment. This result was supported by low-temperature photoluminescence (PL) measurements on a Mns/ZnSe superlattice. No peaks were observed above the ZnSe band gap suggesting that the alignment was not type I. A previously unobserved broad PL peak was seen at about 2.77-2.78 eV, approximately 50 meV below the ZnSe bandgap.