Graphene transistors could cool themselves


RESEARCHERS with the University of Illinois have found graphene transistors have a nanoscale cooling effect which reduces their temperature.

Mechanical science and engineering professor William King and electrical and computer engineering professor Eric Pop led the team, which published the findings in the 3 April advance online edition of the journal Nature Nanotechnology.

Electronics chips are obviously limited in speed and size by the amount of heat they dissipate. This heat is produced by electrons in the current colliding with the device material.

Computers with silicon chips use fans or flowing water to cool the transistors, a process that consumes much of the energy required to power a device.

Researchers say future computer chips made out of graphene could not only be faster than silicon chips, but also operate at a lower power.

However, due to the tiny dimensions involved in graphene, which are carbon sheets one atom thick, a thorough understanding of heat generation and distribution in graphene devices has eluded researchers.

The research team used an atomic force microscope tip as a temperature probe to make the first nanometer-scale temperature measurements of a working graphene transistor.

The measurements revealed that thermoelectric cooling effects can be stronger at the areas where the graphene touches the metal contacts, and this effect overpowers resistive heating, actually lowering the temperature of the transistor.

This self-cooling effect means that graphene-based electronics could require little or no cooling, allowing even greater energy efficiency and increasing graphene’s attractiveness as a silicon replacement.