Electronic Structure of SiO2, Si(x)Ge(1-x)O2, and GeO2 from Photoemission Spectroscopy.

摘要

The valence-band structure of the mixed silicate Si(x)Ge(1-x) was investigated for a range of compositions by x-ray and uv photoemission spectroscopy. Structure in the valence band, which is derived from the oxygen nonbonding orbitals and from the Si-O bonding orbital, is seen to move continuously in initial energy in going from SiO2 to GeO2. The width of the nonbonding bands at the top of the valence band decreases from about 3.3 eV in SiO2 to 2.0 eV in GeO2 in which separate peaks are no longer resolved. The decrease in width of the nonbonding bands is correlated with an increase in the average oxygen-oxygen separation from 2.62 to 2.85 A. The results indicate that the width of the nonbonding bands is largely due to oxygen wave-function overlap. (Author)