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ABSTRACT: The authors report the ozonation of patterned, vertically aligned carbon nanotube (CNT) forests as a method of priming them for subsequent pseudo atomic layer deposition (ψ-ALD) (alternating layer deposition) of silica to produce microfabricated, CNT-templated thin layer chromatography (TLC) plates. Gas phase ozonation simplifies our deposition scheme by replacing two steps in our previous fabrication process: chemical vapor deposition of carbon and ALD of Al2O3, with this much more straightforward priming step. As shown by x-ray photoelectron spectroscopy, ozonation appears to prime/increase the number of nucleation sites on the CNTs by oxidizing them, thereby facilitating conformal growth of silica by w-ALD, where some form of priming appears to be necessary for this growth. (As shown previously, ψ-ALD of SiO2 onto unprimed CNTs is ineffective and leads to poor quality depositions.) In conjunction with a discussion of the challenges of good peak fitting of complex C 1s XP narrow scans, the authors present an analysis of our C 1s data that suggests an increase in oxidized carbon, particularly the C=O group, with increasing oxygen content of the CNT forests. After coating with SiO2, the CNTs are removed by elevated temperature air oxidation, the SiO2 is rehydrated, and the plates are coated with 3-aminopropyltriethoxysilane (APTES). The resulting APTES-coated plates separate various fluorescent dyes giving results that are generally at least as good as those the authors reported previously with our more complicated fabrication/priming scheme. TLC plates with different geometries are microfabricated, where plates with narrower channels show longer run times (lower mobile phase velocities) and plates with narrower features appear to give higher efficiencies.
Journal of Vacuum Science & Technology B Microelectronics and Nanometer Structures 01/2013; 31(3):031803-1.
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Optical Engineering 01/2011; 50(DOI:10.1117/1.3529981):015201. · 0.96 Impact Factor
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Nanoscience and Nanotechnology Letters 01/2011; 3(4):1-7. · 0.53 Impact Factor
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Advanced Functional Materials 01/2011; 21(6):1132 – 1139. · 10.18 Impact Factor
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M.R. Linford,
S. Copeland,
A. Dadson,
R.C. Davis,
D. Jensen,
G. Saini,
V. Shutthanandan,
J. Song,
M.A. Vail, R. Vanfleet,
L.A. Wiest,
R.D. Wyman,
L. Yang
Extended abstract to 'Microscopy and Microanalysis', Portland, OR; 08/2010
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Proc. SPIE 7730, 77301N; 01/2010
