The thermalization of hot carriers and phonons gives direct insight into the scattering
processes that mediate electrical and thermal transport. Obtaining the scattering rates for
both hot carriers and phonons currently requires multiple measurements with
incommensurate timescales. Here, transient extreme-ultraviolet (XUV) spectroscopy on the
silicon 2p core level at 100 eV is used to measure hot carrier and phonon thermalization in
Si (100) from tens of femtoseconds to 200 ps, following photoexcitation of the indirect …