Study of the Ge(111)/GeO2 interface by optical second harmonic spectroscopy

The reflected optical second harmonic intensity from the Ge(111)/GeO2 inter face has been measured in a dry nitrogen atmosphere as a function of the in cident photon energy. The oxide layer was produced by thermally oxidizing a Ge(111) substrate in pule oxygen gas at 823 K. We have found that the SH i ntensity pattern as a function of the sample rotation angle around the surf ace normal changes drastically in the photon energy range near h omega =1.1 7 eV in the p-polarized input and p-polarized output configuration. At this resonance, the anisotropic SH response from the interface has a dominant c ontribution to the SH intensity. (C) 2000 Elsevier Science B.V. All rights reserved.