arXivDaily arXiv每日学术速递 周一至周五更新
arXiv周末暂无论文更新,休息一下吧,周末愉快~~
arXiv 2301.04769cond-mat.mes-hall
收藏

通过局域声子共振实现半导体热学与电学性质的解耦

Semiconductor thermal and electrical properties decoupled by localized phonon resonances

Bryan T. Spann, Joel C. Weber, Matt D. Brubaker, Todd E. Harvey, Lina Yang, Hossein Honarvar, Chia-Nien Tsai, Andrew C. Treglia, M. Lee, Mahmoud I. Hussein, Kris A. Bertness

AI总结:

该研究通过在硅膜表面生长GaN纳米柱,利用局域声子共振在实验上首次实现半导体热学与电学性质的解耦,热导率降低21%而电性能不受影响,打破热电特性权衡,为高效固态能量回收与制冷铺路。

摘要:

热电材料通过固体中的热驱动电荷输运将热量转化为电能,反之则用于制冷。要与传统发电技术竞争,热电材料必须同时具备电导体和热绝缘体的特性。然而,由于载流子和声子的散射机制相互关联,这些特性通常是互斥的。近期亚器件尺度的理论研究表明,覆盖纳米柱的硅膜表现出覆盖全频谱的大量局域声子共振,这些共振与膜中载热声子耦合,共同导致面内热导率降低——而原则上不会影响电学性质,因为纳米柱位于电压产生和电荷输运的通路之外。本研究通过探究表面生长有GaN纳米柱的器件级悬浮硅膜,首次通过实验证明了这一效应。纳米柱使热导率降低高达21%,同时电导率和塞贝克系数保持不变,从而实现了半导体热电性质前所未有的解耦。对聚结纳米柱的热导率测量结果及相应的晶格动力学计算进一步证明,热导率的降低在机制上与声子共振相关。这一发现打破了热电领域长期存在的竞争特性之间的权衡,为工程化高效固态能量回收和制冷铺平了道路。

英文摘要:

Thermoelectric materials convert heat into electricity through thermally driven charge transport in solids, or vice versa for cooling. To be competitive with conventional energy-generation technologies, a thermoelectric material must possess the properties of both an electrical conductor and a thermal insulator. However, these properties are normally mutually exclusive because of the interconnection of the scattering mechanisms for charge carriers and phonons. Recent theoretical investigations on sub-device scales have revealed that silicon membranes covered by nanopillars exhibit a multitude of local phonon resonances, spanning the full spectrum, that couple with the heat-carrying phonons in the membrane and collectively cause a reduction in the in-plane thermal conductivity$-$while, in principle, not affecting the electrical properties because the nanopillars are external to the pathway of voltage generation and charge transport. Here this effect is demonstrated experimentally for the first time by investigating device-scale suspended silicon membranes with GaN nanopillars grown on the surface. The nanopillars cause up to 21 % reduction in the thermal conductivity while the electrical conductivity and the Seebeck coefficient remain unaffected, thus demonstrating an unprecedented decoupling in the semiconductor's thermoelectric properties. The measured thermal conductivity behavior for coalesced nanopillars and corresponding lattice-dynamics calculations provide further evidence that the reductions are mechanistically tied to the phonon resonances. This finding breaks a longstanding trade-off between competing properties in thermoelectricity and paves the way for engineered high-efficiency solid-state energy recovery and cooling.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑