Observation of ion-irradiation induced diffusion in Pd–Si system using synchrotron radiation X-ray photoelectron spectroscopy

Abstract

Diffusion of Si atoms in Pd under energetic ion irradiation is studied in Pd film (100nm)-coated Si using synchrotron radiation X-ray photoelectron spectroscopy. Before irradiation, we observe photoelectron spectra only for Pd, but do not find any trace of Si. After irradiation with 3MeV Si ions or 1MeV O ions, we observe an additional photoelectron component at a binding energy of about 2.2–2.9eV higher than that of Si 1s bulk component. The experimental result implies that the energetic-ion irradiation induces the diffusion of Si atoms from the Si–Pd interface to the Pd layer surface. From the shift of the binding energy, we discuss the chemical state of Si atoms at the Pd surface.