Local Nature of Artificial Homojunction Band Discontinuities

The feasibility of creating homojunction band discontinuities by dipole intralayers was recently demonstrated with photoemission studies. We explored the nature of this intriguing mechanism by studying the effects of several complex intralayers, specifically stacked sequences of dipole intralayers. Quite unexpectedly, we found that the magnitude of the corresponding discontinuities is comparable to those created by individual dipole intralayers. We discuss this result in light of the recently observed [L. Sorba, G. Bratina, G. Ceccone, A. Antonini, J. F. Walker, M. Micovic, and A. Franciosi, Phys. Rev. B 43, 2450 (1991)], similarly unpredicted saturation at low thickness of intralayer-induced heterojunction band discontinuities modifications.