Second-harmonic generation and reflecance-anisotropy spectroscopy of vicinal Si(001)

Spectroscopic second-harmonic generation (SHG) and reflectance-anisotropy spectroscopy (RAS) of native-oxidized vicinal Si(001) with off-cut angles ζ = 0o , 4o , 6o , 8o and 10o from (001) toward [110] are performed. The SHG spectra are first decomposed using the macroscopic Fourier analysis. As a common microscopic analysis for SHG and RAS, we use a simplified bond hyperpolarizability model. The description of the expanded bond model and the result of the calculation are presented. The derived complex hyperpolarizability spectra are compared with the corresponding inverted real and imaginary parts using nonlinear Kramers-Kronig relations, thus confirming the consistency of the developed bond model. RAS and SHG spectra from clean and selectively H2 adsorbed reconstructed vicinal Si(001):6o surfaces are obtained and analyzed in a similar way.