Vicinal Si(111) surfaces studied by optical second-harmonic generation: Step-induced anisotropy and surface-bulk discrimination

Abstract

By modifying a Si(111) surface through the introduction of a variable number of steps, the anisotropic surface and bulk contributions to the optical second-harmonic generation could be determined separately and were found to be of the same order of magnitude for a Si-${\mathrm{SiO}}_{2}$ interface. This approach is based on the lowering of the surface symmetry by the steps and by the apparent enhancement of the nonlinear susceptibility at the step edges.