Chemistry, Department of
First Advisor
Jody G. Redepenning
Date of this Version
Summer 7-2019
Abstract
Graphene is a two-dimensional allotrope of carbon, with several superlative properties, including high electron and hole conductivities, high tensile strength, and chemical robustness. Its chemical and physical properties make it attractive for in use in a myriad of applications, including transistors. However, graphene’s chemical inertness and its physical and electrical properties’ dependency on its conjugated structure make building composite materials with graphene difficult. In 2015, Lipatov, et. al. demonstrated that a film derived from electropolymerized phenol could be used as a dielectric layer on transistor devices fabricated from exfoliated graphene. This thesis extends that research, detailing experiments of phenol and phenol derivative electropolymerization. Several derivatives, such as 4-vinylphenol, 4-chlorophenol, and phloroglucinol, solution conditions, and electropolymerization conditions were investigated. Most derivatives were found to be more porous than the phenol film, as determined by pinhole measurements using electroactive compounds. Interestingly, electropolymerizing phloroglucinol in potassium chloride solution resulted in a cation exchange film. This film may have use as a seed layer for metal oxide atomic layer deposition. Films of various thicknesses were electropolymerized onto devices fabricated from exfoliated, then chemical vapor deposited, graphene. Aluminum oxide atomic layer deposition was then performed, followed by metal or PEDOT:PSS top gates. Unfortunately, all top-gated devices had high leakage currents and were not gateable. A brief investigation into the cause of the high leakage currents was inconclusive.
Advisor: Jody G. Redepenning
Comments
A THESIS Presented to the Faculty of The Graduate College at the University of Nebraska In Partial Fulfillment of Requirements For the Degree of Master of Science, Major: Chemistry, Under the Supervision of Professor Jody Redepenning. Lincoln, Nebraska: July, 2019
Copyright 2019 Christopher Joseph White II