Low-Temperature Synthesis of Graphene and Fabrication of Top-Gated Field Effect Transistors without Using Transfer Processes

Thickness-controlled growth of few-layer and multi-layer graphene was performed at 650 °C by thermal chemical vapor deposition, and top-gated field effect transistors (FETs) were fabricated directly on a large SiO2/Si substrate without graphene-transfer processes. Graphene was synthesized on patterned Fe films. The iron was subsequently etched after both ends of the graphene were fixed by source and drain electrodes, leaving the graphene channels bridging the electrodes all over the substrate. Top-gated FETs were then made after covering the channels with HfO2. The fabricated devices exhibit ambipolar behavior and can sustain a high-density current. The growth mechanism of graphene was also investigated.