Publication Date


Document Type


Committee Members

Angela Campbell (Committee Member), Eva M. Campo (Committee Member), James Grote (Committee Member), Steven Higgins (Committee Member), Gregory Kozlowski (Advisor)

Degree Name

Doctor of Philosophy (PhD)


The main goal of this dissertation was two-fold: first, to study and design a graphene-based transistor environmentally friendly by replacing a standard substrate and gate dielectric with different flexible/rigid and biodegradable films and secondly, to study their effects on graphene's charge carrier mobility. A thin film of deoxyribonucleic acid nucleobase purine guanine deposited by physical vapor deposition onto up to ten layers of graphene that were transferred onto various rigid and flexible substrates was characterized more thoroughly. Several test platforms were fabricated with guanine 1) as a standalone gate dielectric, 2) as the control and 3) as a passivation layer between the graphene and PMMA (polymethylmethacrylate). It was found that the bulk charge carrier mobility of graphene was best maintained and most stable with guanine as a passivation layer between the graphene and PMMA. The optimal transistor device suggested in this research consists of 60 nm PMMA (gate dielectric)/10 nm guanine (passivation layer)/four monolayers of graphene (semiconductor)/Willow glass (substrate). Charge carrier concentration, conductivity type, and electrical resistivity were investigated for these devices as well. In addition, the relative humidity under ambient conditions was studied to determine the effect of moisture and oxygen on graphene alone and on graphene with the gate dielectric material on the top of graphene to determine which dielectric material degrades faster. This study strongly suggests potential application of guanine in the electronics industry because of its high temperature stability.

Page Count


Department or Program

Department of Earth and Environmental Sciences

Year Degree Awarded