By Josh Perry, Editor
A team of researchers led by the University of Houston (Texas) have developed a method for growing boron arsenide crystals with a thermal conductivity of 1,000 W/mK in sizes that are large enough to be used in real-world applications.
Researchers have created a crystal grown from two relatively common mineral elements – boron and arsenic – that demonstrates far higher thermal conductivity than any other semiconductors and metals currently in use. (University of Houston)
According to a report from the university, researchers at the Texas Center for Superconductivity (located on the Houston campus) have grown crystals as large as 4 mm by 2 mm by 1 mm and could grow larger crystals if the process exceeded the 14-day limit of the experiment.
The combination of boron and arsenide defies “the conventional theory that ultrahigh lattice thermal conductivity could only occur in crystals composed of strongly bonded light elements, limited by anharmonic three-phonon processes,” according to the article.
This research matches similar studies that are coming out of labs across the country.
The research was recently published in Science. The abstract read:
“Conventional theory predicts that ultrahigh lattice thermal conductivity can only occur in crystals composed of strongly-bonded light elements, and that it is limited by anharmonic three-phonon processes.
“We report experimental evidence that is a departure from these long-held criteria. We measured a local room-temperature thermal conductivity exceeding 1000 W m−1 K−1 and an average bulk value reaching 900 W m−1 K−1 in bulk boron arsenide (BAs) crystals, where boron and arsenic are light and heavy elements, respectively.
“The high values are consistent with a proposal for phonon band engineering and can only be explained with higher order phonon processes. These findings yield new insight into the physics of heat conduction in solids and show BAs to be the first known semiconductor with ultrahigh thermal conductivity.”