Room-temperature formation of the Ag/GaAs (110) interface

Photoemission yield spectroscopy, low-energy electron diffraction and Auger electron spectroscopy measurements are performed on a set of UHV cleaved GaAs (110) surfaces from n- and p-type crystals as a function of Ag coverage theta which is varied from about 10 -4 monolayer (ML) to a few ML. The variations upon interface formation of the atomic structure, the work function phi , the ionisation energy Phi and the semiconductor band bending are analysed together with the changes of the density of filled surface states in the gap and in the valence band, within about 1 eV from the top. At the forming interface, the contribution of different electron states is demonstrated and their possible origins are discussed. Ag is shown to form an abrupt interface and to grow epitaxially as crystallites forming a non-uniform layer.