Inelastic-electron-scattering investigation of clean and hydrogen-exposed InP(110) surfaces

An electron-energy-loss spectroscopy (EELS) study on clean and hydrogenated InP(110) surfaces in the 1-6-eV loss-energy region is presented. We focused on the dependence of the spectra on the azimuthal angle between the plane of incidence and the [110 BAR] crystallographic direction-the direction of the zigzag atomic chains on the topmost semiconductor layer. An azimuthal dependence of the transition involving surface electronic states has been observed, as seen previously in other III-V semiconductor (110) surfaces. The results are compared with optical measurements, integrated EELS data, and surface band-structure calculations.