Effects of dielectric material properties on graphene transistor performance

Graphene has attracted attention due to its excellent electrical properties; however, the electrical performance of graphene devices, including device hysteresis, mobility, and conductivity, tends to be limited by the supporting dielectric layer properties. In this work, the impact of a dielectric material on a graphene transistor was investigated by fabricating graphene field effect transistors integrated with four different dielectric substrates (SiO2, Al2O3, Si3N4 and hexagonal boron nitride) and by comparing the transistor performances. Results revealed that the carrier transport characteristics of the graphene transistors, including the hysteresis, Dirac point shift, and mobility, were highly correlated with the hydrophobicity-induced charge trapping and surface optical phonon energies of the dielectric materials.