Schematic illustration of a high-speed graphene transistor with a Co2Si–Al2O3 core–shell nanowire as the self-aligned top-gate. Left, schematic of the 3D view of the device layout. D, drain; G, gate; S, source. Right, schematic of the cross-sectional view of the device.
Scientists from UCLA, led by Xiangfeng Duan have developed the fastest graphene transistor to date. Its performance is comparable to the speediest transistors including gallium arsenide and indium phosphide.
The innovation is significant because graphene transistors have great potential for making computers, phones and other electronic devices faster and smaller.
Graphene is the “flake” form of graphite crystal–a honeycomb lattice made of a sheet one carbon atom thick. It has the highest known electron mobility (the speed at which electronic information is transmitted by a material). But current techniques for fabricating graphene-based materials and devices can lead to deterioration in device quality.
While theoretical studies have suggested that graphene nanoribbons could have interesting magneto-electronic properties, with excellent conductivity, most of the graphene research is still confined to the lab due to the difficulty in fabricating electronic device structures at large scales.
In a paper published in the journal Nature, Professors Duan, Yu Huang and Kang Wang outlined how they overcame some of the difficulties in fabricating graphene transistors. They developed a fabrication process for graphene transistors using a nanowire, which is thinner than a human hair, as the gate that switches the transistor on and off.
The team observed a significant enhancement in the conductance of a graphene-nanoribbon transistor when they applied a magnetic field to the structure. It currently is trying to scale up the new fabrication approach and boost the transistor’s speed.
This research is sponsored by a NSF CAREER Grant: Graphene Nanomesh: Band Gap Engineering in Single Layers of Carbon.
High-speed graphene transistors with a self-aligned nanowire gate