SKKU Advanced Institute of Nanotechnology, Sungkyunkwan University, Suwon, 440-746, Korea. Research Center for Time-Domain Nano-Functional Devices, Samsung Advanced Institute of Technology, Youngtong-gu, Suwon-si, 443-803, Korea.
Nanotechnology. 2016 Jul 29;27(30):305703. doi: 10.1088/0957-4484/27/30/305703. Epub 2016 Jun 16.
We demonstrate silicon germanium (SiGe) alloy nanowires (NWs) with Ge nanoparticles (GeNPs) embedded in a SiO2 shell as a material for decreasing thermal conductivity. During thermal oxidation of SiGe NWs to form SiGe-SiO2 core-shell structures, Ge atoms were diffused into the SiO2 shell to relax the strain in the SiGe core, and agglomerated as a few nanometer-sized particles. This structure leads to a large reduction in thermal conductivity due to the GeNP-phonon interaction, while electrical conductivity is sustained because the core of the SiGe alloy NW provides a current path for the charged carriers. The thermal conductivity of the SiGe alloy NWs wrapped with a GeNP-embedded SiO2 shell is 0.41 W m(-1) K(-1) at 300 K.
我们展示了一种硅锗（SiGe）合金纳米线（NWs），其具有嵌入 SiO2 壳中的锗纳米颗粒（GeNPs），作为降低热导率的材料。在 SiGe NW 进行热氧化以形成 SiGe-SiO2 核壳结构的过程中，Ge 原子扩散到 SiO2 壳中，以松弛 SiGe 核中的应变，并聚集成几个纳米大小的颗粒。这种结构导致热导率的大幅降低，这是由于 GeNP-声子相互作用所致，而电导率得以维持，因为 SiGe 合金 NW 的核提供了载流子的电流路径。用嵌入 GeNP 的 SiO2 壳包裹的 SiGe 合金 NW 的热导率在 300 K 时为 0.41 W m(-1) K(-1)。
