Electrostatically Reversible Polarity of Dual-Gated Graphene Transistors

We developed dual-gated graphene transistors in which the transistor polarity (n-type or p-type) is electrostatically reversible by the gate bias of one of the top gates. In this device, a channel is defined as the region between a pair of top gates, where graphene is irradiated by an accelerated helium ion beam to form a defect-induced transport gap. This device features not only a large current ON-OFF ratio of four orders of magnitude but also unipolarity of transistors, which would otherwise be ambipolar. We also show how these polarity-reversible transistors can be used in logic circuits.