Resonant photoemission characterization of SnO

A thick layer of SnO, equivalent in its electronic properties to the bulk material, has been investigated by means of resonant photoemission and the mathematical method of factor analysis. This study has shown that $\mathrm{O}2p,$ $\mathrm{Sn}5s,$ and $\mathrm{Sn}5p$ partial density of states are the main contributions to the valence band of this material. The distribution through the valence band of these partial contributions has been determined by spectral subtraction and factor analysis of the resonance photoemission spectra, as well as by band structure calculation. The resonance behavior (i.e., change in intensity with the photon energy) of these three contributions has been analyzed. The $\mathrm{Sn}5p$ levels present a typical Fano-like behavior with a minimum intensity at about 28 eV and a maximum at 40 eV. The $\mathrm{Sn}5s$ partial density distribution also depicts a change in intensity as a function of the photon energy with a minimum situated at 35 eV and a maximum at 55 eV. Tentatively, this behavior has been linked to the existence of a broad absorption feature detected by electron energy loss spectroscopy and constant final state spectra, both depicting a broad maximum at about 50 eV.