Synthesis of Highly n-Type Graphene by Using an Ionic Liquid

A new N-doped reduced graphene oxide (rGO) field effect transistor (FET) was designed by using an amine-terminated ionic liquids (IL) (1-(3-aminopropyl)-3-methylimidazolium bromide (IL-NH2)) that has a high boiling point. GO was prepared from natural graphite powder by the modified method by Hummers and Offenman using sulfuric acid, potassium permanganate, and sodium nitrate. In the high-resolution scan, the asymmetric N1s XPS spectrum of PrGO-IL was divided into four components, indicating that nitrogen atoms attached to the rGO network were in four different binding states. The intensity ratio of the PrGO-IL and samples subjected to annealing at 400 to 800°C increases from 0.87 to 1.02, indicating an increased disorder. A lower resistance is observed for the as-prepared device prepared by annealing at 800°C compared with the device annealed at 400°C because higher annealing temperatures yielded more effective reduction.