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Bohn, Paul W. Castle, Patrick James 2015-09-25T22:13:21Z 2015-09-25T22:13:21Z 10000-01-01 2005 2005 The goal of this work was to fabricate Au atom-scale junctions as the basis for robust, regenerable, nanostructured sensors to use with mass-limited samples for improved protection of health and safety. Atom-scale junctions were formed between two Au thin film electrodes. The inter-electrode gap was lithographically defined, and a microfluidic channel was aligned over the inter-electrode gap. The inter-electrode gap was reduced with electrodeposition, which was terminated at an atom-scale junction by setting a comparator to trigger a relay at a current corresponding to a junction conductance comparable to the conductance quantum. Based on conductance measurements and estimates from SEM images, atom-scale junctions were successfully formed. Lewis bases were introduced to atom-scale junctions, and the resulting alternating current impedance change was measured. For example, the interfacial scattering from chemisorption of 10 mM hexadecanethiol (HDT) on a 2.6 G0 atom-scale junction caused a normalized impedance change of 71% +/- 1%, with a noise level consistent with a population fluctuation of only 1 HDT molecule. To regenerate the device in situ, the junction was broken with a potential sweep and reformed with comparator-terminated electrodeposition. The atom-scale junction capability to measure small numbers of adsorption/desorption events makes a powerful case for pushing the limits of sensitivity for electrical measurements of single molecule events. Made available in DSpace on 2015-09-25T22:13:21Z (GMT). No. of bitstreams: 2 license.txt: 4848 bytes, checksum: 96035ab3f5e1c23cc7138a224ce498bd (MD5) 3198938.pdf: 3797478 bytes, checksum: db493e607d06b490b175d3b4d883368f (MD5) Previous issue date: 2005 Embargo set by: Seth Robbins for item 85463 Lift date: Forever Reason: Restricted to the U of I community idenfinitely during batch ingest of legacy ETDs Restricted to the U of I community idenfinitely during batch ingest of legacy ETDs U of I Only 142 p. Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2005. http://hdl.handle.net/2142/84182 (MiAaPQ)AAI3198938 eng Chemistry, Analytical Sensing Molecular Adsorption Through Interfacial Electron Scattering in Atom -Scale Junctions text Chemistry Chemistry University of Illinois at Urbana-Champaign Dissertation Ph.D.