X-ray nanoscale profiling of layer-by-layer assembled metal/organophosphonate films.
The nanoscale structure of multilayer metal/phosphonate thin films prepared via a layer-by-layer assembly process was studied using specular X-ray reflectivity (XRR), X-ray fluorescence (XRF), and long-period X-ray standing wave (XSW) analysis. After the SiO(2) X-ray mirror surfaces were functionalized with a monolayer film terminated with phosphonate groups, the organic multilayer films were assembled by alternating immersions in (a) aqueous solutions containing Zr(4+), Hf(4+), or Y(3+) cations and then (b) organic solvent solutions of PO(3)-R-PO(3), where R was a porphyrin or porphyrin-square spacer molecule. The different heavy metal cations provided X-ray fluorescence marker layers at different heights within the different multilayer assemblies. The XSW measurements used a 22 nm period Si/Mo multilayer mirror. The long-period XSW generated by the zeroth-order (total external reflection) through fourth-order Bragg diffraction conditions made it possible to examine the Fourier transforms of the fluorescent atom distributions over a much larger q(z)() range in reciprocal space than previously achieved.
Libera
Joseph A
JA
Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, USA.
Gurney
Richard W
RW
Nguyen
SonBinh T
ST
Hupp
Joseph T
JT
Liu
Chian
C
Conley
Ray
R
Bedzyk
Michael J
MJ
D008567:Membranes, Artificial; D015394:Molecular Structure; D008982:Molybdenum / Q000737:chemistry; D049329:Nanostructures / Q000737:chemistry*; D036103:Nanotechnology / Q000379:methods*; D009942:Organometallic Compounds / Q000737:chemistry*; D009943:Organophosphorus Compounds / Q000737:chemistry*; D012680:Sensitivity and Specificity; D012825:Silicon / Q000737:chemistry; D013052:Spectrometry, X-Ray Emission; D013499:Surface Properties; D028561:Transition Elements / Q000737:chemistry*; D014961:X-Ray Diffraction / Q000379:methods
D008567:Membranes, Artificial; D009942:Organometallic Compounds; D009943:Organophosphorus Compounds; D028561:Transition Elements; D008982:Molybdenum; D012825:Silicon