Measurement of the ZnSe:MnSe:ZnSe heterojunction valence-band discontinuities

UV-photoemission spectroscopy was used to measure directly the valence-band discontinuity ΔEv for both sides of a MnSe layer which was sandwiched between two ZnSe layers by the molecular beam epitaxy method. ΔEv is 0.16±0.05 eV for each interface; the valence-band edge Emaxv of the wider gap MnSe semiconductor lies within the ZnSe gap. The interface-pinning position of the Fermi level appears at 1.74 eV above Emaxv of ZnSe. It is concluded that interfacial electrostatic dipoles are small compared to the observed shift in Emaxv of MnSe, which lends a qualitative support to Tersoff’s model [Phys. Rev. Lett. 52, 465 (1984); Phys. Rev. B 30, 4874 (1984)] of heterojunction band offsets.