The energetics and kinetics of processes involving interface states at silicon (111) surfaces in aqueous fluoride solutions were determined using in situ impedance spectroscopy. In the dark, we observe electrically active surface states with densities in the range $2\times {10}^{10}$ to $1\times {10}^{12}{\mathrm{cm}}^{-2\mathrm{}}$ dependent on the surface chemistry. The surface states are physically the same, independent of $p\mathrm{H}$, with a capture cross section of $1\times {10}^{-16\mathrm{}}{\mathrm{cm}}^2$. Measurements under illumination show that recombination occurs at different interface states than those observed in the dark.

• Received 22 June 1995

DOI:https://doi.org/10.1103/PhysRevLett.76.1521