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Exploring Atomic Force Microscopy To Probe Charge Transport Through Molecular Films And For The Development Of Combinatorial Force Microscopy

Posted on:2012-08-22Degree:Ph.DType:Dissertation
University:University of Alberta (Canada)Candidate:Chisholm, Roderick AFull Text:PDF
GTID:1450390011953876Subject:Chemistry
Abstract/Summary:
Since the invention of the atomic force microscope (AFM), this technology has had profound implications in the study of material science and molecular biology. The ability to visualize and perform quantitative analysis of the nanoscale properties of surfaces has provided great insights into these nanoscale landscapes. The present dissertation manuscript exploits this technology for the measurement of charge transport through molecular films and the development of combinatorial force microscopy.;This dissertation manuscript also describes the development of the quantitative interrogation opposing chemical libraries involved in combinatorial inverted atomic force microscopy. Tipless cantilever's were patterned with chemically modified nanorods. These modified nanorods were then used as chemical identifiers during a combinatorial force microscopy experiment and for the first time 16 interactions were monitored within one experiment in a continuous medium. Thus, providing excellent for the validation that combi-AFM is a truly quantitative high-throughput technology.;Firstly, this work probed, for the first time, charge transport through molecular films derived from diazonium salts grafted to carbon electrodes using conductive atomic force microscopy. We found the charge transport properties of a molecular junction are dependent upon the chemical structure of the molecular film. We also investigated the effect of molecular film compression and deformation has on charge transport. In this, we observed increases in current densities associated with increases in applied load to the molecular film. Furthering these initial findings, PPF/NAB/Cu molecular junctions were fabricated having junction sizes ranging between micro-scale and nanoscale. The charge transport experiments reveal an agreement of electron transport properties between the metal deposited PPF/NAB/Cu junction and a PPF/NAB/Cu AFM tip junction at an applied load of approximately 60nN. This form of molecular layer charge transport control may potentially open new horizons for integration of molecular films into the microelectronics industry.
Keywords/Search Tags:Charge transport, Molecular, Atomic force, Development
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