InP(001) surface structure and interaction with atomic hydrogen

Structure and electronic properties of clean and hydrogen-terminated InP surfaces are studied by reflectance anisotropy spectroscopy (RAS), Auger electron spectroscopy (AES), high resolution energy electron loss spectroscopy (HREELS), low energy electron diffraction (LEED) and soft X-ray photoelectron spectroscopy (SXPS). Clean surfaces were prepared either by sputtering and annealing or decapping (As/P-cap). Both preparation methods lead to the same type of (2 X 4) surface structure with slightly different ratios of indium to phosphorus. The corresponding structural changes of the surface during hydrogen exposure are investigated by LEED, surface electronic modifications are observed by RAS. Medium exposures of atomic hydrogen break In bonds at the surface while high exposures lead to an In enrichment of the surface. With increasing hydrogen exposure the optical anisotropy is lifted. (C) 1998 Elsevier Science B.V.