Experimental observation of high thermal conductivity in boron arsenide

Abstract

Improving the thermal management of small-scale devices requires developing materials with high thermal conductivities. The semiconductor boron arsenide (BAs) is an attractive target because of ab initio calculation indicating that single crystals have an ultrahigh thermal conductivity. We synthesized BAs single crystals without detectable defects and measured a room-temperature thermal conductivity of 1300 watts per meter-kelvin. Our spectroscopy study, in conjunction with atomistic theory, reveals that the distinctive band structure of BAs allows for very long phonon mean free paths and strong high-order anharmonicity through the four-phonon process. The single-crystal BAs has better thermal conductivity than other metals and semiconductors. Our study establishes BAs as a benchmark material for thermal management applications and exemplifies the power of combining experiments and ab initio theory in new materials discovery.

Photoluminescence mapping and time-domain thermo-photoluminescence for rapid imaging and measurement of thermal conductivity of boron arsenide

“…Based on well-established relationship between PL and crystal quality and the relationship between crystal quality and thermal conductivity  proved by recent demonstrations and theories 4,5,6,7,8,21 , we speculate that a strong PL must lead to a high . To make use of these relationships for thermal conductivity measurement, we take one step further and utilize confocal PL imaging to evaluate  of large BAs crystals.…”

“…The interest in BAs increased suddenly in 2013 when first-principles calculations predicted BAs as a highly thermal conductive () material with a value comparable to that of diamond and much higher than the most commonly used heat-sink materials like copper and silicon carbide 4,5 . Subsequent intense research led to successful synthesis and verification of the predicted high- material in 2018 by three groups 6,7,8 , which opens up new opportunities for more basic research as well as potential applications as a thermal sink material compatible with silicon 9 . However, despite BAs being first studied in the late 50s of the last century 1 , its actual bandgap value has not been well settled.…”

Ab initio investigation of single-layer high thermal conductivity boron compounds

“…In particular, boron compounds, including cubic boron phosphide (c-BP) and boron arsenide (c-BAs), were predicted to have high thermal conductivities [4,5]. Importantly, experimental work has demonstrated the synthesis of high-quality crystals and measured thermal conductivity values of 500 and 1300 W/m K, respectively, in c-BP [6] and c-BAs [7][8][9]. These studies exemplify the power of combined synthesis, characterization, and ab initio theory for developing design rules for new materials discovery.…”

Strain and electric field tuning of 2D hexagonal boron arsenide

“…Computational studies using density functional theory (DFT) reveal that boron arsenide (BAs) can form a stable 2D hexagonal structure similar to hexagonal boron nitride showing a semiconducting nature with a bandgap of approximately 1 eV [30,31]. Boron arsenide forms a cubic 3D structure with a remarkably high thermal conductivity [32,33], a property the 2D structure hexagonal boron arsenide (h-BAs) is expected to share [34,35] with application perspectives as coolant in nanodevices. In [30] they explore the effect of biaxial strain on the electronic structure and find a transition to a metallic state at a biaxial strain of 14%.…”