Surface Recombination on the Si(111) 2×1 Surface

We have directly monitored population changes in surface states as photoexcited bulk carriers recombine at a semiconductor surface. By observing the time dependence of the photoexcited carriers in the conduction band, as well as the transient population in the ${\mathrm{\pi }}^{\mathrm{*}}$ surface state, a detailed, microscopic model of transient surface recombination is constructed for the Si(111)2×1 surface which includes transient surface-charging effects on the bulk transport self-consistently.