Ultrafast carrier dynamics on the Si(100)2×1 surface

We present a study of ultrafast carrier dynamics on the clean Si(100)2×{}1 surface using time-resolved photoemission spectroscopy. A rapid thermalization inside the surface band is observed, and the carrier relaxation occurs on a time scale of a few hundred femtoseconds to a few picoseconds depending on the initial state energy. The relaxation time increases as the initial state energy decreases with respect to the band minimum.