论文标题
孔硅膜的峰热电源因子
Peak thermoelectric power factor of holey silicon films
论文作者
论文摘要
纳米结构硅的热电特性尽管最初的承诺并未完全理解。虽然异常低的导热率吸引了很多工作，但纳米结构对功率因数的影响大多引起了人们的注意。虽然与大量相比，初始报告没有发现功率因数的任何重大变化，但与类似掺杂的体积相比，随后对P型硅纳米线的详细测量结果显示出明显降低的Seebeck系数。由于声子边界散射，还原与声子阻力贡献的消失是一致的。在这里，我们报告了对不同纳米结构孔硅膜的测量值，以测试是否观察到类似的声子阻力损失。通过设计在同一样品上测量所有特性的实验，我们表明，尽管这些薄膜在可比较的掺杂时具有接近大量的电导率，但它们的热电图较小。数据与丢失声子阻力一致。在120-230 nm之间的颈部距离处，最佳掺杂的功率因数为$ \ sim $ 50％。这些见解可用于基于纳米结构硅的未来热电设备的实际设计。
The thermoelectric properties of nanostructured silicon are not fully understood despite their initial promise. While the anomalously low thermal conductivity has attracted much work, the impact of nanostructuring on the power factor has mostly escaped attention. While initial reports did not find any significant changes to the power factor compared to the bulk, subsequent detailed measurements on p-type silicon nanowires showed a stark reduction in the Seebeck coefficient when compared to similarly doped bulk. The reduction is consistent with the disappearance of the phonon drag contribution, due to phonon boundary scattering. Here, we report measurements on a different nanostructure, holey silicon films, to test if similar loss of phonon drag can be observed. By devising experiments where all properties are measured on the same sample, we show that though these films possess electrical conductivity close to that in the bulk at comparable doping, they exhibit considerably smaller thermopower. The data are consistent with loss of phonon drag. At neck distances between 120 - 230 nm, the power factor at optimal doping is $\sim$ 50 percent that of the bulk. These insights are useful in the practical design of future thermoelectric devices based on nanostructured silicon.
