Large transport gap modulation in graphene via electric-field-controlled reversible hydrogenation

Graphene is of interest in the development next-generation electronics due to its high electron mobility, flexibility and stability. However, graphene transistors have poor on/off current ratios because absence a bandgap. One approach introduce an energy gap use hydrogenation reaction, which changes into insulating graphane with sp3 bonding. Here we show that electric field can be used control conductor-to-insulator transitions microscale via reversible electrochemical organic liquid electrolyte containing dissociative hydrogen ions. The fully hydrogenated exhibits lower limit sheet resistance 200 Gohm/sq, resulting field-effect 10^8 at room temperature. devices also exhibit endurance, up one million switching cycles. Similar behaviours are observed bilayer graphene, while trilayer remains highly conductive after hydrogenation. Changes lattice, transformation from sp2 hybridization, confirmed by in-situ Raman spectroscopy, supported first-principles calculations.