Electronic properties of hydrogen exposed III-V semiconductor surfaces

A critical review of experimental results aiming at determining the atomic geometry and the electronic properties of the hydrogenated (110) surfaces of III-V semiconductor compounds is given. Results deal mainly with the prototype GaAs(110) surface. Experimental results include photoemission, electron energy loss, metastable deexcitation spectroscopy, Auger electron spectroscopy, photoelectron diffraction and grazing incidence X-ray diffraction data. A unified picture for the hydrogenated surface can be derived. It is characterized by an almost nonrelaxed substrate (or even counter-relaxed), absence of gap states and, up to one monolayer of coverage, by a surface order and an almost preserved substrate stoichiometry. Higher exposures induce surface etching with changes of Ga to As concentration ratio.