The Effect of Humidity on the Interaction of Dimethyl Methylphosphonate (DMMP) Vapor with SiO2 and Al2O3 Surfaces, Studied Using Infrared Attenuated Total Reflection Spectroscopy
Abstract
S1. Procedure for determining SiO2 thickness using XPS: Figures S1 and S2 show typical XPS data for SiO2 films prepared as described in the main text. The Si 2p data (Fig. S2a) show a peak from the substrate, which is partially resolved into a 2p1/2 and 2p3/2 spin-orbit doublet, and a peak from SiO2, which is too broad to resolve. Other features, due to SiOx (x<2) at the interface, are not readily observable. The relative integrated area, after background subtraction, is given by (S1) where I is the integrated area of the SiO2 or the Si peak, N is the number of Si atoms per unit volume in either material, is the Si 2p photoionization cross-section, and Vs is the volume sampled. In the situation of interest here, all the other terms influencing the XPS intensity (detector gain, analyzer transmission, etc.) cancel in the ratio. The exponential term in the denominator accounts for the attenuation of the substrate peak by the oxide layer of thickness.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 2010
- Accession Number
- ADA533155
Entities
People
- Victor M. Bermudez
Organizations
- United States Naval Research Laboratory