Photoelectron spectroscopy study of Pu thin films on Si

X-ray photoelectron spectroscopy and high-resolution ultraviolet photoelectron spectroscopy studies were performed on Pu sputter deposited on Si. The intermixing of Pu with Si at deposition can produce different types of Pu–Si systems, which can be subsequently modified by Ar+ ion bombardment. Annealing of thick Pu films leads to a reaction and formation of a compound with stoichiometry approximately PuSi2. Three pronounced narrow spectral features in the energy range to 1 eV below the Fermi energy, which exhibit an anomalous temperature dependence, can be attributed to the 5f5 final-state multiplet, originating from the 5f6 admixture in the ground state.