Selected Publications

Thumbnail of figure from publication
David S. Jensen, Supriya S. Kanyal, Vipul Gupta, Richard Vanfleet, Robert C. Davis, and Matthew R. Linford (et al.)
Some of us recently described the fabrication of thin layer chromatography (TLC) plates from patterned carbon nanotube (CNT) forests via direct infiltration/coating of the CNTs by low pressure chemical vapor deposition (LPCVD) of silicon from SiH4, followed by high temperature oxidation of the CNTs and Si. Herein we present an improved microfabrication process for the preparation of these TLC plates. First, a few nanometers of carbon and/or a thin film of Al2O3 is deposited on the CNTs. This method of priming the CNTs for subsequent depositions appears to be new. X-ray photoelectron spectroscopy confirms the presence of additional oxygen after carbon deposition. After priming, the plates are coated by rapid, conformal deposition of an inorganic material that does not require subsequent oxidation, i.e., by a fast pseudo atomic layer deposition (psi-ALD) of SiO2 from trimethylaluminum and tris(tert-butoxy)silanol. Unlike devices described previously, faithful reproduction of the features in the masks is still observed after oxidation. A bonded, amino phase on the resulting plates shows fast, highly efficient separations of fluorescent dyes (plate heights in the range of 1.6-7.7 mu m). Extensive characterization of the new materials by TEM. SEM, EDAX, DRIFT, and XPS is reported. A substantially lower process temperature for the removal of the CNT scaffold is possible as a result of the already oxidized materials used. (C) 2012 Elsevier B.V. All rights reserved.
Thumbnail of figure from publication
Anthony C. Pearson, Jianfei Liu, Elisabeth Pound, Bibek Uprety, Adam T. Woolley, Robert C. Davis, and John N. Harb
DNA origami is a promising tool for use as a template in the design and fabrication of nanoscale structures. The ability to engineer selected staple strands on a DNA origami structure provides a high density of addressable locations across the structure. Here we report a method using site-specific attachment of gold nanoparticles to modified staple strands and subsequent metallization to fabricate conductive wires from DNA origami templates. We have modified DNA origami structures by lengthening each staple strand in select regions with a 10-base nucleotide sequence and have attached DNA-modified gold nanoparticles to the lengthened staple strands via complementary base-pairing. The high density of extended staple strands allowed the gold nanoparticles to pack tightly in the modified regions of the DNA origami, where the measured median gap size between neighboring particles was 4.1 nm. Gold metallization processes were optimized so that the attached gold nanoparticles grew until gaps between particles were filled and uniform continuous nanowires were formed. Finally, electron beam lithography was used to pattern electrodes in order to measure the electrical conductivity of metallized DNA origami, which showed an average resistance of 2.4 k Omega per metallized structure.
Thumbnail of figure from publication
Anthony C. Pearson, Bhupinder Singh, Matthew R. Linford, Barry Lunt, and Robert Davis
The data in present solid-state storage solutions is ephemeral. This paper outlines research to study materials for a permanent solid-state storage solution.
Thumbnail of figure from publication
Anthony C. Pearson, Bhupinder Singh, Matthew R. Linford, Barry M. Lunt, and Robert C. Davis
The data in present solid-state storage solutions is ephemeral. This paper outlines research to study materials for a permanent solid-state storage solution.
Thumbnail of figure from publication
Barry M. Lunt, Anthony Pearson, Robert Davis, Hao Wang, Sarah Jamieson, and Matthew R. Linford
The data in present solid-state storage solutions is ephemeral. This paper outlines research to develop a permanent solid-state storage solution based on new materials that are compatible with current IC manufacturing processes.
Thumbnail of figure from publication
David Brough, Lawrence Barrett, Richard Vanfleet, Sterling Cornaby, and Robert C. Davis (et al.)

As micro and nanotechnology continue to advice into products, durability, reliability and robustness become important factors. One application where micro technology needs such qualities is X-ray windows. X-ray windows consist of free standing thin film membranes made from low Z elements. An ideal X-ray window is thin enough to allow for soft X-ray transmission and yet is strong enough to maintain a vacuum. X-ray windows are used to analyze samples in microscopes and hand held devices for mining and other applications. These membranes in hand held devices need to be able to withstand impacts due to dropping or jarring of the device. Shock test studies have been performed on electronics and membranes related to biological system, but literature showing the robustness of free standing membranes is not ready found. In this study free standing thin film membranes’ ability to withstand repeated shocks created by using a bar contact pendulum shock apparatus is investigated. A comparison of shock resistance of X-ray window membrane materials specifically silicon nitride and beryllium will be presented.