Interaction of atomic hydrogen with InP(100): Comparison with the cleaved surface interaction

Abstract

Photoemission yield spectroscopy (PYS) in the photon energy range from 3.8 to 6.7 eV has been used to characterize clean InP(100) and study its interaction with atomic hydrogen. Some measurements in low energy electron diffraction, Auger electron spectroscopy and electron energy loss spectroscopy have also been performed. The surface was cleaned by cycles of ion sputtering and annealing in ultrahigh vacuum. It is shown to contain a slight excess of In metal; the ionization energy of InP is that of the clean cleaved surface, and an effective density of surface states which exists at the top of the valence band is minimized when the surface is clean. Upon interaction with H, an adsorption and a decomposition stage are evidenced as with cleaved InP. However, during the adsorption stage on the (100) face, the ionization energy remains equal to that of the clean surface, while it decreased on (110). The decomposition stage on the (100) face, as on (110), leads to the formation of In metal and a phosphine-like compound which remains adsorbed on the surface and is at the origin of a peculiar phenomenon observed in PYS. The system is, however, far less stable than on the cleaved surface since the P-hydrogenated species desorbs spontaneously at room temperature leaving an In covered surface which appears insensitive to H.