Silicon L_{2, 3} near-edge fine structure in confined volumes

Silicon L2,3 edge spectra have been obtained with 0.2-0.3 eV resolution in 5-50 nm thick specimens. The shapes of the spectra are thickness-dependent, becoming indistinct in thickness less than about 20 nm. In the lateral direction, however, the core scattering is insensitive to the presence of a surface until the probe actually hits the surface. Lifetime broadening increases from 0.1 eV for an infinite foil to 0.4 eV at 6 nm thickness. This behavior can be explained qualitatively if the plasmon wake potential influences the spatial extent of the final state for the core absorption. © 1993.