DNA-nucleobases: gate dielectric/passivation layer for flexible GFET-based sensor applications

The main goal of this research was to maintain the bulk charge carrier mobility of graphene, after deposition of the gate dielectric layer used for making transistor devices. The approach was introducing a thin film of deoxyribonucleic acid (DNA) nucleobase purine guanine, deposited by physical vapor deposition (PVD), onto layers of graphene that were transferred onto various flexible substrates. Several test platforms were fabricated with guanine as a standalone gate dielectric, as the control, and guanine as a passivation layer between the graphene and PMMA. It was found that the bulk charge carrier mobility of graphene was best maintained and most stable using guanine as a passivation layer between the graphene and PMMA. Other transport properties, such as charge carrier concentration, conductivity type and electrical resistivity were investigated as well. This is an important first step to realizing high performance graphene-based transistors that have potential use in bio and environmental sensors, computer-processing and electronics.