A transistor includes at least three terminals comprising a gate electrode, a source electrode and a drain electrode, an insulating layer disposed on a substrate, and a semiconductor layer disposed on the substrate, wherein a current which flows between the source electrode and the drain electrode is controlled by application of a voltage to the gate electrode, where the semiconductor layer includes a graphene layer and at least one of a metal atomic layer and a metal ion layer, and where the metal atomic layer or the metal ion layer is interposed between the graphene layer and the insulating layer.