In-Situ Vibrational Study of SiO2/liquid Interface

The surface of SiO2 in contact with a liquid has been studied in situ by Fourier transform infrared spectroscopy, electrochemistry and ab initio quantum chemical calculations. Experimental issues arising from the cell designed have been addressed, notably the influence of the medium above the SiO2 film on the line shape of the Si–O vibrations. Using electrical potential control of the surface with electrochemistry, the hydrated states of the SiO2 surface have been identified, featuring a neutral SiOH species and pentavalent Si(OH)OH− anionic centers

An infrared study of H8Si8O12H8Si8O12 cluster adsorption on Si(100) surfaces

Motivated by a controversy about the proper interpretation of x-ray photoelectron spectra of Si/SiO2Si/SiO2 interfaces derived from the adsorption of H8Si8O12H8Si8O12 spherosiloxane clusters on Si(100) surfaces, we have studied the adsorption geometry of the H8Si8O12H8Si8O12 clusters on deuterium-passivated and clean Si(100) surfaces by using external reflection infrared spectroscopy. Access to frequencies below 1450 cm−11450cm−1 was made possible through the use of specially prepared Si(100) samples which have a buried metallic CoSi2CoSi2 layer that acts as an internal mirror. A comparison of the infrared spectrum of the clusters on a deuterium-passivated Si(100) surface at 130 K with an infrared spectrum of the clusters in a carbon tetrachloride solution reveals that the clusters are only weakly physisorbed on the D/Si(100) surface and also provides evidence for the purity of the cluster source. We also present infrared spectra of clusters directly chemisorbed on a clean Si(100) surface and show evidence that the clusters are adsorbed on the Si(100) via attachment by one vertex. A complete assignment of the observed vibrational features, for both physisorbed and chemisorbed clusters, has been made based upon comparisons with the results obtained in ab initio calculations using gradient-corrected density functional methods. © 1998 American Institute of Physics.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/69818/2/JCPSA6-108-20-8680-1.pd