REACTION AND EPITAXIAL REGROWTH AT THE NI/GAAS(001) INTERFACE - A STATE-SPECIFIC X-RAY PHOTOELECTRON DIFFRACTION INVESTIGATION

We demonstrate, for the first time, that state-specific x-ray photoelectron diffraction can be used to determine the structural environment of reacted substrate atoms at a metal/semiconductor interface. Such measurements reveal that extensive reactivity at the Ni/GaAs(001) interface is followed by epitaxial regrowth of a CsCl phase in which Ni atoms occupy one sublattice and disrupted Ga and As atoms occupy the other sublattice.