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The effect of P segregation on the electronic structure of Fe2P has been studied by soft X-ray photoelectron spectroscopy (PES). As the Fe2P surface was sputtered by Ar+ ion (2 kV, 10 min), the amount of P atoms in the surface region was reduced. The amount of surface P atoms was further reduced by annealing the sputtered surface at elevated annealing temperatures up to about 400 °C, and it was increased by annealing at temperatures higher than 400 °C. It was deduced from the analyses of the P 2p core-level PES spectra that desorption of P atoms weakly bonded to the surface, which are thought to be formed through the sputtering process, proceeded when the surface was annealed at temperatures lower than 500 °C. On the other hand, it was also deduced from the PES study that the segregation of bulk P atoms toward the surface proceeded when the annealing temperature was higher than 300 °C. These two processes were competing at 300–500 °C, leading to the minimum amount of surface P atoms at approximately 400 °C. The PES spectra were measured after annealing the sputtered surface at various temperatures, and it was found that the stabilization of the 3d states of surface Fe atoms due to the bonding with surrounding P atoms was ineffective irrespective of the amount of P atoms on Fe2P.

Interaction between an air-stable orange-colored dye molecule, acridine orange base (AOB), and single-crystal surfaces of ZnO(101̅0), (0001), and (0001̅) is examined by synchrotron-radiation-excited photoelectron spectroscopy and X-ray absorption spectroscopy. AOB adsorbs molecularly on the ZnO surfaces to form chemical bonds with the surface O atoms. AOB tends to lie flat on the surfaces, whereas a more stand-up orientation is preferred on the AOB-crowded surfaces. AOB adsorption induces downward bending of the ZnO band with the largest amount on ZnO(0001̅), followed by the ZnO(101̅0) and ZnO(0001) surfaces, indicating an electron donor property of AOB. The energy level alignment at the AOB/ZnO interface is determined and is found to be characterized by a type-II heterojunction, which favors the charge transfer of the excited electron from AOB to ZnO.

Vanadium oxide films were grown on Ag(100) by vanadium deposition in O2 and subsequent annealing at 450 °C. It was found that at least three types of ordered V oxide films, which showed (1 × 1), hexagonal, and (4 × 1) LEED patterns, were formed on Ag(100) depending on the O2 pressure during deposition and conditions during postannealing. The films with the hexagonal and (1 × 1) periodicities were characterized by photoelectron spectroscopy (PES) and near-edge X-ray absorption fine structure (NEXAFS) analysis. The film with the (1 × 1) periodicity was ascribed to a VO(100) film. On the other hand, the film with the hexagonal periodicity was found to be composed of V2O3, and the analysis of the LEED pattern revealed that the lattice parameter of the hexagonal lattice is 0.50 nm, which is very close to that of corundum V2O3(0001) (0.495 nm).