Electronic Properties And Electron Dynamics Of The Si(001)(2 X 1) Surface With C-Defects

Both the time-resolved two-photon photoelectron spectroscopy and scanning tunneling microscopy are utilized for investigating the role of the C-defects in the electronic property and dynamics of the p-type Si(001)(2 x 1) surface. It is found that the C-defect causes Fermi-level pinning when its density is more than 0.05 monolayer. The change in the inverse of the product of the bulk-to-surface electron transition rate S and in the extinction lifetime 7 of the surface excited electron is examined as a function of the C-defect density, and it was found that the change doubles when the C-defect density increases from 0 to 0.1 monolayer on the surface. This indicates that the C-defect plays an important (but limited) role in the surface carrier dynamics of Si(001).