Analysis of angle-resolved electron energy loss in XPS spectra of Ag, Au, Co, Cu, Fe and Si

Angle-resolved XPS measurements on a series of transition metal samples and one Si sample are carried out to investigate the dependence of surface los ses on electron exit angle. The inelastic background in the transition meta ls is analyzed using the universal cross-section lambda K(T) = BT/(C + T-2) (2). We find that a consistent primary spectrum F(E) may be obtained for al l angles, and for all the metal samples, by adjusting the values of C and B in a well specified way. The variation in C and B models the effect of sur face losses on lambda K(T). The validity of the approach is tested by perfo rming an equivalent analysis of REELS spectra, from which the exact cross-s ections can be determined. We find a good agreement between the universal c ross-sections and the exact results. For Si the plasmon structure is more n arrow and surface effects appear as a separate peak in the loss function. I n this case, the procedure described above cannot be applied, and we invest igate more qualitatively the magnitude of the surface effects with varying exit angle. (C) 1999 Elsevier Science B.V. All rights reserved.