Zincblende–CdSe on GaSb(110): Characterization of epitaxial growth and electronic structure

Substrate-stabilized pseudomorphic growth offers the chance to study the electronic structure of a particular semiconductor in different crystal structures, and to investigate the influence of structural differences on bulk and surface states. We have grown layers of CdSe in the zincblende modification on cleaved GaSb(110) surfaces by molecular beam epitaxy. The growth mode and structure of the overlayer were studied by means of low energy electron diffraction and photoemission using synchrotron radiation. The attenuation of substrate core level intensities with CdSe deposition indicates layerwise growth. Interface reaction leads to the liberation of Sb, which floats on the growth front, and the formation of a Ga-Se compound, as signaled by changes in substrate and overlayer core level line shape. The valence band offset for this lattice-matched interface system is 1.09 eV, such that the heterojunction is of the staggered type, in agreement with predictions based on the dielectric midgap energy model.