Graphene electronics on the horizon | mirage news

A pressing search in the field of nanoelectronics is the search for a material that can replace silicon. Graphene has shown promise for decades. But its potential faltered along the way, due to harmful processing methods and the lack of a new electronic paradigm to embrace it. With silicon nearly maxed out to accommodate faster computing, the next great nanoelectronics platform is needed now more than ever.

walter sirRegents’ Professor at the physics school at the Georgia Institute of Technology, has taken a pivotal step by making the case for a successor to silicon. De Heer and his collaborators developed a new nanoelectronics platform based on graphene, a single sheet of carbon atoms. The technology is compatible with conventional microelectronics manufacturing, a necessity for any viable alternative to silicon. In the course of investigating him, published in Nature Communications, the team may also have discovered a new quasiparticle. Their discovery could lead to smaller, faster, more efficient and more sustainable computer chips, and has potential implications for high-performance and quantum computing.

“The power of graphene lies in its flat two-dimensional structure that is held together by the strongest known chemical bonds,” de Heer said. “It was clear from the start that graphene can be miniaturized much more than silicon, allowing for much smaller devices, while operating at higher speeds and producing much less heat. This means that, in principle, more devices can be packed on a single graphene chip than with silicon.”

In 2001, de Heer proposed an alternative form of electronics based on epitaxial graphene, or epigraphene, a layer of graphene that spontaneously formed on silicon carbide crystal, a semiconductor used in high-power electronics. At that time, the researchers found that electrical currents flow without resistance along the edges of epigraphene and that graphene devices can be seamlessly interconnected without metallic wires. This combination enables a form of electronics that relies on the unique light-like properties of graphene electrons.

“Quantum interference has been observed in carbon nanotubes at low temperatures, and we expect to see similar effects in epigraphene ribbons and lattices,” de Heer said. “This important feature of graphene is not possible with silicon.”

building the platform

To create the new nanoelectronics platform, the researchers created a modified form of epigraphene on a silicon carbide crystal substrate. In collaboration with researchers at the Tianjin International Center for Nanoparticles and Nanosystems at Tianjin University, China, they produced unique silicon carbide chips from electronic-grade silicon carbide crystals. The graphene itself was grown in de Heer’s lab at Georgia Tech using proprietary ovens.

The researchers used electron beam lithography, a method commonly used in microelectronics, to carve the graphene nanostructures and weld their edges to the silicon carbide chips. This process mechanically stabilizes and seals the edges of the graphene, which would otherwise react with oxygen and other gases that could interfere with the movement of charges along the edge.

Finally, to measure the electronic properties of their graphene platform, the team used a cryogenic apparatus that allows them to record its properties from near zero to room temperature.

Observing the state of the edge

The electrical charges the team observed in the edge state of graphene were similar to photons in an optical fiber that can travel great distances without scattering. They found that the charges traveled tens of thousands of nanometers along the edge before dispersing. Electrons in graphene in earlier technologies could only travel about 10 nanometers before colliding with tiny imperfections and scattering in different directions.

“What’s special about electric charges at edges is that they stay on the edge and continue at the same rate, even if the edges aren’t perfectly straight,” said Claire Berger, a professor of physics at Georgia Tech and director of research at the Center. French National Scientific Research Center in Grenoble, France.

In metals, electrical currents are carried by negatively charged electrons. But contrary to the researchers’ expectations, their measurements suggested that the edge currents were not carried by electrons or holes (a term for positive quasiparticles indicating the absence of an electron). Rather, the currents were carried by a very unusual quasiparticle that has no charge and no energy, and yet moves without resistance. The components of the hybrid quasiparticle were observed to travel on opposite sides of the edges of the graphene, despite being a single object.

The unique properties indicate that the quasiparticle could be one that physicists have been hoping to exploit for decades: the elusive Majorana fermion predicted by Italian theoretical physicist Ettore Majorana in 1937.

“Developing electronic products using this new quasiparticle in perfectly interconnected graphene networks is a game changer,” de Heer said.

It will probably be another five to 10 years before we have the first graphene-based electronics, according to de Heer. But thanks to the team’s new epitaxial graphene platform, the technology is closer than ever to crowning graphene the successor to silicon.

/ Public statement. This source organization/author(s) material may be ad hoc in nature, edited for clarity, style, and length. The views and opinions expressed are those of the author(s). View in full here.

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