Optical second harmonic spectroscopy of semiconductor surfaces: advances in microscopic understanding

Even-order non-linear optical spectroscopy has emerged as an unusually sensitive technique for noninvasive analysis of surfaces and buried interfaces of centrosymmetric materials. The forefront challenges are: to develop reliable microscopic computational methods for calculating and interpreting measured surface non-linear spectra; to relate non-linear surface spectra quantitatively to linear optical surf ace probes such as reflectance-difference spectroscopy (RDS); and to develop convenient methods for acquiring nonlinear optical spectra over bandwidths (several electron-volts) that encompass multiple electronic surface resonances. We review recent advances in both calculation and measurement of non-linear spectra, with emphasis on reconstructed and adsorbate-covered silicon surfaces in epitaxial growth environments. Copyright (C) 2001 John Wiley & Sons, Ltd.