G. Erley et W. Daum, SILICON INTERBAND-TRANSITIONS OBSERVED AT SI(100)-SIO2 INTERFACES, Physical review. B, Condensed matter, 58(4), 1998, pp. 1734-1737
We report on a type of Si interband transitions at Si(100)-SiO2 interf
aces that has no equivalent in the bulk of crystalline silicon. These
transitions, leading to strong resonances in optical second-harmonic-g
eneration spectra with energies of 3.6-3.8 eV, are energetically locat
ed between the E-1 and E-2 critical points of bulk Si. We assign these
transitions to Si atoms without T-d lattice symmetry at the boundary
between crystalline Si and the SiOx transition region. We also report
on a strong blueshift of the E-2 transitions at the interface.