Silicon-based thermoelectric nanosystems

硅基热电纳米系统

• 批准号: 121821990
• 负责人: Professor Dr. Karl Brunner
• 金额: --
• 依托单位: Institut für Halbleitertechnik
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 财政年份: 2009
• 资助国家: 德国
• 起止时间: 2008-12-31 至 2015-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/121821990?language=en
• 关键词: Silicon; based; thermoelectric; nanosystems

Thermoelectric (TE) generators directly mounted into the exhaust gas return (EGR) cooler can help to harvest a portion of the huge amount of day-to-day wasted heat. They have to endure constant and cycling temperature loading up to around 500°C, which cannot be fulfilled by Bi2Te3 -based TE material but by silicon. Bulk silicon, however, has a low figure of merit (ZT ~ 0.01) owing to high thermal conductivity. In the first funding period we found that by patterning silicon into nanowires of ~ 200 nm in diameter in combination with a rough nanorod surface thermal conductivity was strongly reduced corresponding to ZT ~ 0.14 at conservative assumptions for the Seebeck coefficient and the resistivity. Further reduction of thermal conductivity and thus improvement towards ZT > 1 resulting in efficiencies necessary for a practical harvesting device (10 to 20 %) is planned for the second funding period which shall be achieved by 1) enhancing the surface-to-volume ratio and thus phonon surface scattering via further reducing the nanowire diameter to < 100 nm or by adding an inner surface (Si nanotube), 2) engineering the nanowire surface for more efficient phonon roughness scattering, 3) integration of multilayer structures into silicon nanowires (Si/SiGe, Si/SiOx, 28Si/29Si) to exploit the effect of heterointerfaces, boundaries, alloys and isotopes on phonon scattering.

直接安装在排气回流（EGR）冷却器中的热电（TE）发电机可以帮助恢复每天浪费的大量热量的一部分。他们必须忍受恒定和骑自行车的温度加载，高达约500°C，而基于BI2TE3的TE材料无法实现，而硅则无法实现。然而，由于导热率很高，大量硅具有低功绩（ZT〜0.01）。在第一个融资期间，我们发现，通过将硅直径构成约200 nm的纳米线，并与粗糙的纳米棒表面热导率相结合，在Seebeck Core的保守假设下，与ZT〜0.14相对应，对应于Seebeck Core的ZT〜0.14。 Further reduction of thermal conductivity and thus improvement towards ZT > 1 resulting in efficiency necessary for a practical harvesting device (10 to 20%) is planned for the second funding period which shall be achieved by 1) enhancing the surface-to-volume ratio and thus phonon surface scattering via further reducing the nanowire diameter to < 100 nm or by adding an inner surface (Si nanotube), 2) engineering the nanowire surface for more有效的声子粗糙度散射，3）将多层结构的整合到硅纳米线中（Si/Sige，Si/Siox，28Si/29si），以利用异性框，边界，合金，同型和同位素对声子散射的影响。