UH Physicist Joins Project to Develop New High Thermal Conducting Material

Multi-University Project Seeks Thermal Conducting Material that Will Be More Efficient Than Diamond

A University of Houston physicist will participate in a $7.5 million collaboration to develop a new material with thermal conductivity higher than that of diamonds.

Zhifeng Ren, MD Anderson Professor of physics, is working to produce a thermal conductor with high tech cooling applications.Zhifeng Ren, MD Anderson Professor of physics, is working to produce a thermal conductor with high tech cooling applications.The work, funded by the U.S. Navy’s Multidisciplinary University Research Initiative, involves researchers from around the country, working to create an effective and affordable thermal conductor of boron arsenide.

Zhifeng Ren, MD Anderson Professor of physics at UH’s College of Natural Sciences and Mathematics, said previous research predicted that boron arsenide would perform better than diamond as a thermal conductor. A thermal conductor allows energy, in the form of heat, to be transferred within the material; electronic devices require high thermal conductors in order to avoid overheating.

Ren will receive $1.3 million to study the material in single crystals or thin film.

The project is led by Li Shi, professor of mechanical engineering at the University of Texas at Austin. Other participating universities include Boston College, the Massachusetts Institute of Technology, the University of Illinois at Urbana-Champagne, and the University of California, Los Angeles.

Shi noted that Ren’s research group has reported the first thermal conductivity measurement of boron arsenide. “They have proposed novel methods to grow this and other potentially ultrahigh thermal conductivity materials,” he said. “Their efforts are instrumental for the success of this multidisciplinary project.”

Diamond is considered one of the best thermal conductors at room temperature, with thermal conductivity of more than 2,000 watts per meter per Kelvin. That’s five times higher than copper.

But it’s expensive, and Ren said researchers hope to prove a theory developed by Boston College physicist David Broido that cubic boron arsenide could deliver thermal conductivity on par with the industry standard set by diamond, potentially allowing for improved high tech cooling applications.

Ren’s lab began experimenting with the compound last year, making a single crystal of the material. The crystal had defects but reached thermal conductivity of 200 watts/meter/Kelvin, about 10 percent of what Broido predicted, he said.

It indicated they were on the right track, however. “This was very preliminary work, so there is hope that this material can have very high thermal conductivity,” he said. “If we are successful, it would be a big improvement for high-powered electronics.”

Making the material is difficult, as boron has a high melting point – almost 2,075 degrees Centigrade, or 3,767 degrees Farenheit – while arsenic vaporizes between 400 degrees and 500 degrees C. Beyond those complications, Ren’s group will have to produce a crystal between 10 and 100 times larger than that created last year – or about one millimeter – in order to accurately measure the results.

“We have to demonstrate we can make bigger crystals, and that the crystals have thermal conducting properties that are truly high,” he said.

- Jeannie Kever, University Media Relations