Investigation of the Ag/InP(110) interface formation

Abstract

Photoemission yield spectroscopy (PYS), low energy electron diffraction (LEED) and Auger electron spectroscopy (AES) measurements are performed on a set of UHV cleaved InP(110) surfaces from n- and p-type crystals as a function of Ag coverage θ which is varied from about 10 −3 monolayer (ML) to 100 ML. Ag is shown to form an abrupt interface and no pseudo epitaxy of Ag is observed below 100 ML. The variations upon interface formation of the atomic structure, the work function φ, the ionization energy Φ 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 0.6 eV from the top. The pinning of the Fermi level observed on n-type samples at ≅4.8 eV, giving then a band bending of 0.35 eV, and the decrease of the work function on p-type samples with θ are related to the observed interface states the possible origin of which is discussed and compared to the AgGaAs(110) system.