Graphene transistor could create smarter electronic devices
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A new transistor made from graphene is said to achieve 'a record high switching performance' which could improve the performance of future electronic devices. The new transistor has been developed by a team from the University of Southampton at the new Southampton Nanofabrication Centre.
According to Dr Zakaria Moktadir, pictured, of the Nano research group at the University's School of Electronics and Computer Science (ECS), his research into graphene – the world's thinnest material – led to the development of graphene field effect transistors (GFETs) with a unique channel at nanoscale. Dr Moktadir believes graphene could potentially replace, or be used in conjunction with silicon integrations. "CMOS downscaling is reaching its limits and we need to find a suitable alternative," he said. "Other researchers had looked at graphene as a possibility, but found that one of the drawbacks was that graphene's intrinsic physical properties make it difficult to turn off the current flow."
Dr Moktadir discovered that by introducing geometrical singularities (such as sharp bends and corners) in bilayer graphene nanowires, the current could be turned off efficiently.
And, according to Prof Hiroshi Mizuta, head of the Nano group, this engineering approach has achieved an on/off switching ratio 1000 times higher than previous attempts. "Enormous effort has been made across the world to pinch off the channel of GFETs electrostatically, but the existing approaches require either the channel width to be much narrower than 10nm or a very high voltage to be applied vertically across bilayer graphene layers," Mizuta observed. "This hasn't achieved an on/off ratio which is high enough, and is not viable for practical use."
Dr Moktadir developed the transistor using the new helium ion beam microscope and a focused gallium ion beam system.
"This is a breakthrough in the ongoing quest to develop advanced transistors as we progress beyond our current cmos technology," said Prof Harvey Rutt, head of the School of Electronics and Computer Science. "It will have major implications for next generation computer, communication and electronic systems. Introducing geometrical singularities into the graphene channel is a new concept which achieves superior performance while keeping the GFET structure simple and therefore commercially exploitable."
Having created the transistor, Dr Moktadir is now undertaking further research to understand the mechanism which causes the current to stop flowing in the channel, testing its reliability and performance under various noise and temperature conditions.
