A research team from Aalto University has successfully realized 5-carbon-atoms wide metallic graphene nanoribbons (GNR) experimentally.
The research indicates that these single-atom-thick graphene nanoribbons can be used as metallic interconnects in microprocessors. The team demonstrated the fabrication of GNR and succeeded in measuring their electronic structures. The findings of the research has been published in the journal, Nature Communications.
Graphene nanoribbons have tremendous applications in future nanoelectronics – where the size of the wire is in atomic scales. In all probabilities, graphene will outperform copper due to its high conductance and resistance to electro-migration – the breakdown mechanism in thin metallic wires.
Graphene nanoribbons have always been demonstrated as having semiconducting properties which hamper their use as interconnects. Professor Peter Liljeroth and his team, from Atomic Scale Physics and Surface Science groups used theoretical calculations and showed that certain widths of atomically precise graphene nanoribbons are nearly metallic.
The researchers used state-of-the-art scanning tunneling microscopy (STM) to probe the material structure and its properties with atomic resolution. The fabrication of the nanoribbon is based on chemical reactions on a surface.
“With this technique, we measured the properties of individual ribbons and showed that ribbons longer than 5 nanometers exhibit metallic behavior,” said Dr Amina Kimouche, the lead author of the study.
Dr Ari Harju, from the Quantum Many-Body Physics group complemented the experimental findings which predict that when the width of ribbons is increased atom-by-atom, every third width should be nearly metallic with a small band gap. Quantum mechanics dictates that when the system becomes smaller, the band gap increases. Graphene, with its extraordinary electronic properties, can work differently.
The experiments pave the way for graphene usage in future electronics, where they could potentially replace copper as the interconnect material. Further study will focus on all-graphene devices that combine the metallic and semiconducting properties of graphene nanostructures.
Image courtesy of Aalto University