The impact of Sn on Si_1-xGe_x through its thermal conductivity and phonon properties was investigated to develop an attractive material for thermoelectric devices. The Si-rich polycrystalline Si_1-x-yGe_xSn_y alloy was synthesized by ball-milling technique. The as-synthesized alloy had substitutional Sn content of 1.60%, which it maintained as high as 0.54% after sintering at 1000 C. The thermal conductivity was found to be reduced by the introduction of this tiny amount of Sn. Inelastic X-ray scattering measurements were carried out and we observed the longitudinal acoustic phonon mode superimposed along all crystallographic directions. In addition, the signal that originated from a local vibration at the Ge-related local structure was also successfully detected. It was found that the introduction of Sn affects the local vibration mode in the alloy. It is proposed that the incorporation of Sn atom into the local structure to make Ge–Sn pairs be considered to reduce the material’s thermal conductivity in addition to the mass difference effect.

研究了Sn对Si _1-x Ge _x的热导率和声子特性的影响，以开发出一种有吸引力的热电器件材料。富硅多晶Si _1-xy Ge _x Sn _y通过球磨技术合成了该合金。合成后的合金的Sn替代含量为1.60％，在1000℃烧结后仍保持在0.54％。通过引入少量的Sn可以降低热导率。进行非弹性X射线散射测量，我们观察到沿所有晶体学方向叠加的纵向声子声子模。另外，还成功地检测到源自与Ge有关的局部结构处的局部振动的信号。发现Sn的引入影响合金中的局部振动模式。建议将Sn原子掺入局部结构以形成Ge-Sn对，以减少材料的热导率，此外还具有质量差异效应。