Soft-x-ray–induced core-level photoemission as a probe of hot-electron dynamics in ${\mathrm{SiO}}_2$

The line shape of the bulk Si 2p core-level photoemission peak is found to be strongly dependent on the thickness of ${\mathrm{SiO}}_2$ overlayers through which the electrons are transmitted. This effect is strongly energy dependent. We demonstrate that it arises from strong energy-dependent carrier relaxation in ${\mathrm{SiO}}_2$, and show how the effect may be used, in conjunction with Monte Carlo simulations, to extract energy-dependent scattering rates for electron-phonon and electron-electron scattering.