Interface properties and valence-band discontinuity of MnS/ZnSe heterojunctions

Tetrahedrally bonded, metastable zinc-blende single-crystalline, single-phase MnS was grown by molecular-beam epitaxy on ZnSe buffer layers grown on GaAs(100) substrates. The interface between MnS and ZnSe was studied by transmission electron microscopy and x-ray photoelectron spectroscopy. The valence-band discontinuity in β-MnS/ZnSe heterostructures was measured by x-ray-induced photoelectron spectroscopy. The valence-band discontinuity is not resolved in valence-band spectra from the interface, thereby implying that it is small. We therefore determined the discontinuity from the separation of the core levels at the interface and in reference samples of ZnSe and β-MnS. The results indicate that the valence-band discontinuity at the β-MnS/ZnSe interface is small (about 150 meV) and that the band alignment is of type II. This result agrees with low-temperature photoluminescence measurements on MnS/ZnSe superlattices.