Institute of Industrial Science , The University of Tokyo , Tokyo 153-8505 , Japan.
PRESTO , Japan Science and Technology Agency , Saitama 332-0012 , Japan.
ACS Appl Mater Interfaces. 2019 Mar 27;11(12):12027-12031. doi: 10.1021/acsami.8b21003. Epub 2019 Mar 14.
We propose a simple, low-cost, and large-area method to increase the thermoelectric figure of merit (ZT) in silicon membranes by the deposition of an ultrathin aluminum layer. Transmission electron microscopy showed that short deposition of aluminum on a silicon substrate covers the surface with an ultrathin amorphous film, which, according to recent theoretical works, efficiently destroys phonon wave packets. As a result, we measured 30-40% lower thermal conductivity in silicon membranes covered with aluminum films while the electrical conductivity was not affected. Thus, we have achieved 40-45% higher ZT values in membranes covered with aluminum films. To demonstrate a practical application, we applied this method to enhance the performance of a silicon membrane-based thermoelectric device and measured 42% higher power generation.
我们提出了一种简单、低成本、大面积的方法，通过沉积一层超薄的铝层来提高硅膜的热电器件综合性能（ZT）。透射电子显微镜表明，在硅衬底上短时间沉积铝会在表面形成一层超薄的非晶薄膜，根据最近的理论工作，这种薄膜可以有效地破坏声子波包。因此，我们测量到覆盖有铝膜的硅膜的热导率降低了 30-40%，而电导率没有受到影响。因此，我们在覆盖有铝膜的硅膜中实现了 40-45%更高的 ZT 值。为了展示实际应用，我们将这种方法应用于增强基于硅膜的热电器件的性能，并测量到 42%更高的发电功率。
