Specular X-Ray Reflectivity and Small Angle Neutron Scattering for Structure Determination of Ordered Mesoporous Films

Published

September 1, 2005

Author(s)

B D. Vogt, Hae-Jeong Lee, Wen-Li Wu, Yiping Liu

Abstract

The structure of mesoporous materials, in terms of morphology and orientation, is critical for numerous applications. X-ray reflectivity (XR) and small angle neutron scattering (SANS) are used for the non-destructive, structural characterization of a thin film containing cylindrical mesopores. By rotating the film during the SANS experiment, an average 3D representation of the mesoporous film can be made. The crystal structure of the cylindrical mesopores is not hexagonal, but rather rectangular with a conical angle of 57 0.8 in Fourier space.The degree of planar orientation of the cylindrical mesopores can be determined from the width of the Bragg reflection in specular XR. Approximately 25 repeat layers at both interfaces are aligned in the plane of the film. This was confirmed using cross section transmission electron microscopy (TEM). An anomalous decrease in reflected intensity was observed following the Bragg reflections due to the scattering Form factor of the cylinders aligned in-plane

Citation

Journal of Physical Chemistry B

Volume

109 No 39

Pub Type

Journals

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Keywords

low k dielectric, mesoporous film, reflectivity, small angle neutron scattering

Citation

Vogt, B. , Lee, H. , Wu, W. and Liu, Y. (2005), Specular X-Ray Reflectivity and Small Angle Neutron Scattering for Structure Determination of Ordered Mesoporous Films, Journal of Physical Chemistry B, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=852507 (Accessed October 11, 2025)