Time-Resolved Study of Silicone Surface Recombination.

The recently developed technique of two-photon time- and angle- resolved photoemission spectroscopy has been used to observe the dynamics of surface state populations directly as photoexcited bulk carriers recombine on a semiconductor surface with a well known electronic structure. The surface chosen for this study is the clean, cleaved Si(111)2X1 surface. These observations have allowed us to construct a detailed and comprehensive model for electron-hole recombination on this surface which incorporates and is consistent with all previously obtained data on its electronic structure and dynamics. Transient surface charging effects which occur as the surface state populations evolve were found to strongly influence the flow of bulk carriers toward the surface and were included in the model self-consistently.