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The room temperature deposited α-P/GaAs(100) interfaces have been studied by XPS, UPS, and LEED. The results show that P is adsorbed as clusters on the surface of GaAs at the initial stage of the interface formation, α-P film is formed as the deposition amount is further increased. The valence structures of the films so obtained are similar to those of plasma deposited α-P:H films. There are about one monolayer of P atoms bonded to Ga atoms of the substrate at the interface, α-P overlayer results in 0.2 eV lowering of GaAs surface barrier.

The application of HREELS to the study of the Ag(100)/Na+O2 system reveals the presence of molecularly adsorbed oxygen species at room temperature. This may help explain why alkali metals can enhance the selectivity of an Ag catalyst towards the formation of C2H4O.

The ultraviolet photoelectron spectroscopy of GaAs (100) surface (4×1) structure has been measured by using a polarized UV light source. From the differential spectra between the UPS of the clean surface and the surface with adsorbed oxygen, the surface state peak located within 2eV below valence band maximum could be identified. According to the spectra obtained with s- and p-polarized light and the selection rule of electron transition, it could be shown that this surface state cosists of three peaks: the peak at 0.5eV below valence band maximum corresponding to the bridge bond states of surface Ga atoms, the peak at 0.7eV resulting from the bridge bond states of surface As atoms, and the peak at 1.3eV related to the dangling bond states.

The room temperature adsorption of water on clean and sodium predeposited InP(lll) surface has been studied by UPS and HREELS. The sticking coefficient of water on InP(lll) surface increases significantly as the surface is covered with 0.3 moiiolayer of sodium. This sticking coefficient enhancement could be shown to be related to the charge transfer between the sodium atoms and the surface phosphorous atoms. Water species adsorb On the surface mainly in the form of undissociated molecules. The existence of P-H bond related loss energy peak at 282 meV observed in HREELS suggests that a portion of water molecules may interact with sodium atoms predeposited on the surface or possibly decomposed on the surface to release free hydrogen atoms which could make bonding with surface phosphorous atoms.