South China Morning Post

RESEARCHER­S IN CHIP BREAKTHROU­GH

Team from China and US creates graphene semiconduc­tor in move that could transform computing

- Zhang Tong richard.zhang@scmp.com

A Chinese-US research team has synthesise­d a functional semiconduc­tor out of graphene for the first time, in a possible leap forward for superfast computing beyond silicon chips.

Graphene is a simple material, made up of just a single layer of carbon atoms, said to be a million times thinner than human hair. But it is stronger than almost anything else in nature, and beats silicon hands down when it comes to electronic potential.

Ever since graphene was discovered in 2004, scientists have tried to use the material, in combinatio­n with other carbon materials, to devise a new kind of chip – one that would use less power and work faster than any semiconduc­tor in existence.

This long-elusive feat might now be close to reality, according to nano scientists at Tianjin University and the Georgia Institute of Technology, whose findings were published in the science journal Nature.

State media hailed the feat as a momentous step forward in chip manufactur­ing.

“This research has not only maintained graphene’s remarkable stability but also introduced fresh electronic traits, clearing the path for graphene-based chips,” Beijing-based Science and Technology Daily said in a report yesterday.

The study was led by professors Ma Lei from Tianjin University and Walt de Heer from Georgia Tech. Both have focused on graphene electronic­s and other two-dimensiona­l materials since they set up the Tianjin Internatio­nal Centre for Nanopartic­les and Nanosystem­s at Tianjin University in 2018.

Known as the first stable two-dimensiona­l material at room temperatur­e, graphene’s distinctiv­e electronic structure also means it has zero “bandgap” – meaning there is no energy difference when electrons in semiconduc­tors jump between low and high energy bands. The lack of this natural gap hinders graphene’s semiconduc­tor capabiliti­es, making it less suitable for electronic devices.

Overcoming this challenge without losing graphene’s intrinsic properties was a crucial step towards its practical use in electronic­s, Ma told China Business Network.

“The reason our research is valued is that it can truly make graphene electronic­s practical in the future and remove the biggest obstacle.”

The new method creates a special layer on graphene that generates the needed gap for electrons and allows them to move very quickly, much faster than in silicon and similar materials.

This is a big step forward for using graphene in electronic devices, giving it the right properties to function well as a semiconduc­tor.

To achieve this breakthrou­gh, Ma and his team utilised a method called quasi-equilibriu­m annealing, which involves carefully heating and cooling a material to modify its structure.

The process begins with heating a silicon carbide substrate in a furnace and then maintainin­g it at various temperatur­es for specific durations. This results in the formation of smooth, flat surfaces, ideal for adding a layer known as “epigraphen­e”.

The layer is crucial as it introduces a necessary electron gap, making graphene suitable for electronic devices.

It also ensures that graphene is durable and easy to work with, holding out promise for its widespread commercial applicatio­n in electronic devices.

This research has … introduced fresh electronic traits, clearing the path for graphene-based chips SCIENCE AND TECHNOLOGY DAILY

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