Scanning Tunneling Microscopy combined with optical excitation techniques is used to study non-equilibrium electronic properties of clean silicon surfaces with high spatial resolution. Tunneling potentiometry is performed to measure the excess carrier distributions via the surface photovoltage effect. Well-ordered regions of Si(111)-(7×7) show a uniform surface photovoltage effect, while strong decreases are observed near defects. The decreases in the photovoltage are attributed to an increase in the rate of recombination of electron-hole pairs in the vicinity of the defects.