Extreme Materials Design for Thermal Transport and Energy Conversion

Controlling thermal transport is critical for many applications including electronics and energy technologies. In this talk, I will highlight my group's recent efforts [1-6] in creating innovative materials and devices to push the boundaries of heat dissipation. First, I'll discuss our advancements in developing emerging semiconductors with high thermal conductivity and their integration with wide-bandgap/ultra-wide bandgap semiconductors to enhance heat dissipation in power electronics. Notably, we discovered cubic boron arsenide (BAs) and boron phosphide (BP) with a high thermal conductivity up to 1300 W/mK at room temperature, surpassing most common semiconductors and metals [1]. We've successfully integrated BAs with GaN HEMTs [2], achieving a record thermal boundary conductance and outperforming diamond/SiC cooling devices. Using self-assembly manufacturing [3], we've developed scalable and flexible high-conductivity BAs-polymer interfaces for efficient cooling in LEDs and wearables. Moreover, our fundamental study has explored BAs as a showcase platform for high-order phonon anharmonicity physics [4] and non-perturbative quantum theory [5]. Finally, I’ll discuss our recent advances in solid-state thermal regulation for heat flow and phonon control [6]. References:[1] <i>Science</i> 361, 575-578 (2018). [2] <i>Nature Electronics</i> 4, 416-423 (2021). [3] <i>Nature Communications</i> 12, 1284 (2021). [4] <i>Nature</i> 612, 459-464 (2022). [5] <i>Phys. Rev. B</i> 108, L140302 (2023). [6] <i>Science</i>, to appear.