# The Structure of Self-Assembled Monolayers of Alkylsiloxanes on Silicon: A Comparison of Results from Ellipsometry and Low-Angle X-Ray Reflectivity

 Title: The Structure of Self-Assembled Monolayers of Alkylsiloxanes on Silicon: A Comparison of Results from Ellipsometry and Low-Angle X-Ray Reflectivity Author: Wasserman, Stephen R.; Whitesides, George M.; Tidswell, Ian M.; Ocko, Ben M.; Pershan, Peter S.; Axe, John D. Note: Order does not necessarily reflect citation order of authors. Citation: Wasserman, Stephen R., George M. Whitesides, Ian M. Tidswell, Ben M. Ocko, Peter S. Pershan, and John D. Axe. 1989. The structure of self-assembled monolayers of alkylsiloxanes on silicon: A comparison of results from ellipsometry and low-angle x-ray reflectivity. Journal of the American Chemical Society 111(15): 5852-5861. Access Status: Full text of the requested work is not available in DASH at this time (“dark deposit”). For more information on dark deposits, see our FAQ. Full Text & Related Files: Wasserman_Structure.pdf (1.450Mb; PDF) Abstract: The thicknesses of C10-C18 alkylsiloxane monolayers on silicon-silicon dioxide substrates have been measured with ellipsometry and low-angle X-ray reflection. Although, for any given sample, thicknesses measured by the two methods agree to within experimental error, ellipsometric measurements are systematically larger by approximately $$2 \mathring{A}$$. This difference may result from variations in the sensitivity of the two techniques to the structure of the interface between silicon dioxide and the alkylsiloxane monolayer. The X-ray reflectivity measurements provide evidence that these organic monolayers do not build up as island structures and demonstrate that the approximate area projected by each alkyl group in the plane of the monolayer is $$~21 \pm 3 \mathring{A}^2$$. Preliminary studies indicate that this technique can be used to follow the changes in the structure of a monolayer which result from chemical transformations. The influence of damage that is induced by X-ray radiation on these measurements is discussed. Published Version: doi:10.1021/ja00197a054 Citable link to this page: http://nrs.harvard.edu/urn-3:HUL.InstRepos:10357462 Downloads of this work: