Silicon nanowires (SiNWs) have attracted attention as promising high efficiency thermoelectric materials by significantly improving the thermoelectric efficiency of silicon. Here, we have fabricated cobalt silicide/silicon heterostructure on both ends of nanowires using self-aligned silicide (salicide) process. By forming cobalt silicide (CoSi 2 ) layer on SiNWs, the thermal conductivity of SiNWs with diameters of 200, 350, and 500 nm decrease to 25.1, 31.3, and 38.1 W·m -1 ·K -1 , respectively, which is about 8% reduction on average. Since the phonon nanoinclusion scattering is influenced by the density of the nanoinclusions, the thermal conductivity tends to decrease as the volume fraction of CoSi2 in SiNWs increases. The Seebeck coefficient of the heterostructured nanowires increases to 255 μV/K, which is mainly attributed to the low-energy charge carrier filtering effect due to the Schottky barrier at the CoSi 2 /Si interfaces. The measurements show that the figure-of-merit ZT of the heterostructured nanowires is improved by 10% on average compared with the conventional SiNWs. Consequently, the CoSi 2 /Si heterostructured nanowires enhance the thermoelectric properties of SiNWs effectively by suppressing phonon transport and improving electron flow.

中文翻译：

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硅化钴-硅异质结构纳米线的增强热电性能


硅纳米线（SiNW）作为一种有前途的高效热电材料，通过显着提高硅的热电效率而引起人们的关注。在这里，我们使用自对准硅化物（自对准硅化物）工艺在纳米线的两端制造了钴硅化物/硅异质结构。通过在SiNW上形成硅化钴(CoSi 2 )层，直径为200、350和500 nm的SiNW的热导率分别降低至25.1、31.3和38.1 W·m -1 ·K -1 ，约为平均减少8%。由于声子纳米夹杂物散射受纳米夹杂物密度的影响，因此随着SiNWs中CoSi2体积分数的增加，热导率趋于降低。异质结构纳米线的塞贝克系数增加至255 μV/K，这主要归因于CoSi 2 /Si界面处肖特基势垒的低能载流子过滤效应。测量结果表明，与传统的SiNW相比，异质结构纳米线的ZT平均提高了10%。因此，CoSi 2 /Si异质结构纳米线通过抑制声子输运和改善电子流动，有效增强SiNW的热电性能。