Nav: Home

High-power electronics keep their cool with new heat-conducting crystals

July 05, 2018

CHAMPAIGN, Ill. -- The inner workings of high-power electronic devices must remain cool to operate reliably. High internal temperatures can make programs run slower, freeze or shut down. Researchers at the University of Illinois at Urbana-Champaign and The University of Texas, Dallas have collaborated to optimize the crystal-growing process of boron arsenide - a material that has excellent thermal properties and can effectively dissipate the heat generated in electronic devices.

The results of the study, published in the journal Science, mark the first realization of previously predicted class of ultrahigh thermal conductivity materials.

Boron arsenide is not a naturally occurring material, so scientists must synthesize it in the lab, the researchers said. It also needs to have a very specific structure and low defect density for it to have peak thermal conductivity, so that its growth happens in a very controlled way.

"We studied the structural defects and measured the thermal conductivity of the boron arsenide crystals produced at UT Dallas," said co-author David Cahill a professor and head of the department of materials science and engineering at Illinois. "Our experiments also show that the original theory is incomplete and will need to be refined to fully understand the high thermal conductivity."

Most of today's high-performance computer chips and high-power electronic devices are made of silicon, a crystalline semiconducting material that does an adequate job of dissipating heat. But in combination with other cooling technology incorporated into devices, silicon can handle only so much, the team said.

Diamond has the highest known thermal conductivity - about 15 times that of silicon - but there are problems when it comes to using it for thermal management of electronics. "Although diamond has been incorporated occasionally in demanding heat-dissipation applications, the cost of natural diamonds and structural defects in manmade diamond films make the material impractical for widespread use in electronics," said co-author Bing Lv, a physics professor at UT Dallas.

"The boron arsenide crystals were synthesized using a technique called chemical vapor transport," said Illinois postdoctoral researcher Qiye Zheng. "Elemental boron and arsenic are combined while in the vapor phase and then cool and condense into small crystals. We combined extensive materials characterization and trial-and-error synthesis to find the conditions that produce crystals of high enough quality."

The Illinois team used electron microscopy and a technique called time-domain thermoreflectance to determine if the lab-grown crystals were free of the types of defects that cause a reduction in thermal conductivity.

"We measured dozens of the boron arsenide crystals produced in this study and found that the thermal conductivity of the material can be three times higher than that of best materials being used as heat spreaders today," Zheng said.

The next step in the work will be to try other processes to improve the growth and properties of this material for large-scale applications, the researchers said.
-end-
The Office of Naval Research and the Air Force Office of Scientific Research supported this study.

Editor's notes:

To reach David Cahill, call 217-333-6753; email d-cahill@illinois.edu.

To reach Bing Lv, email blv@utdallas.edu.

The paper "High thermal conductivity in cubic boron arsenide crystals" is available online and from the U. of I. News Bureau.

University of Illinois at Urbana-Champaign

Related Thermal Conductivity Articles:

Graphene substrate improves the conductivity of carbon nanotube network
Scientists at Aalto University, Finland, and the University of Vienna, Austria, have combined graphene and single-walled carbon nanotubes into a transparent hybrid material with conductivity higher than either component exhibits separately.
Scientists' design discovery doubles conductivity of indium oxide transparent coatings
esearchers at the University of Liverpool, University College London (UCL), NSG Group (Pilkington) and Diamond Light Source have made an important design discovery that could dramatically improve the performance of a key material used to coat touch screens and other devices.
Conductivity at the edges of graphene bilayers
For nanoribbons of bilayer graphene, whose edge atoms are arranged in zigzag patterns, the bands of electron energies which are allowed and forbidden are significantly different to those found in monolayer graphene.
Scientists can now control thermal profiles at the nanoscale
Scientists have designed and tested an experimental system that uses a near-infrared laser to actively heat two gold nanorod antennae to different temperatures.
Ionic thermal up-diffusion boosts energy harvesting
Recently nanofluidic salinity gradient energy harvesting via ion channels or membranes has drawn increasing concerns due to the advances in materials science and nanotechnology, which exhibits much higher power density than the macro reverse electrodialysis systems, indicating its potential to harvest the huge amount blue energy released by mixing seawater and river water and enhance power extracted for osmotic heat engines.
More Thermal Conductivity News and Thermal Conductivity Current Events

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Erasing The Stigma
Many of us either cope with mental illness or know someone who does. But we still have a hard time talking about it. This hour, TED speakers explore ways to push past — and even erase — the stigma. Guests include musician and comedian Jordan Raskopoulos, neuroscientist and psychiatrist Thomas Insel, psychiatrist Dixon Chibanda, anxiety and depression researcher Olivia Remes, and entrepreneur Sangu Delle.
Now Playing: Science for the People

#537 Science Journalism, Hold the Hype
Everyone's seen a piece of science getting over-exaggerated in the media. Most people would be quick to blame journalists and big media for getting in wrong. In many cases, you'd be right. But there's other sources of hype in science journalism. and one of them can be found in the humble, and little-known press release. We're talking with Chris Chambers about doing science about science journalism, and where the hype creeps in. Related links: The association between exaggeration in health related science news and academic press releases: retrospective observational study Claims of causality in health news: a randomised trial This...