Department of Chemical Engineering, Texas Materials Institute, Center for Nano- and Molecular Science and Technology, The University of Texas at Austin, Austin, Texas 78712-1062, USA.
Dalton Trans. 2013 Sep 21;42(35):12675-80. doi: 10.1039/c3dt50875g.
A synthetic route to crystalline silicon (Si) nanowires with an amorphous Si shell is reported. Trisilane (Si3H8) and Sn(HMDS)2 are decomposed in supercritical toluene at 450 °C. Sn(HMDS)2 creates Sn nanoparticles that seed Si nanowire growth by the supercritical fluid-liquid-solid (SFLS) mechanism. The Si : Sn ratio in the reaction determines the growth of amorphous Si shell. No amorphous shell forms at relatively low Si : Sn ratios of 20 : 1, whereas higher Si : Sn ratio of 40 : 1 leads to significant amorphous shell. We propose that hydrogen evolved from trisilane decomposition etches away the Sn seed particles as nanowires grow, which promotes the amorphous Si shell deposition when the higher Si : Sn ratios are used.
本文报道了一种具有非晶态硅壳的晶体硅（Si）纳米线的合成途径。三硅烷（Si3H8）和 Sn（HMDS）2 在 450°C 的超临界甲苯中分解。Sn（HMDS）2 生成 Sn 纳米颗粒，通过超临界流体-液体-固体（SFLS）机制为 Si 纳米线生长提供晶种。反应中的 Si：Sn 比决定了非晶态 Si 壳的生长。在相对较低的 Si：Sn 比为 20：1 时，不会形成非晶壳，而较高的 Si：Sn 比为 40：1 会导致显著的非晶壳。我们提出，三硅烷分解产生的氢气在纳米线生长时会刻蚀掉 Sn 晶种颗粒，当使用较高的 Si：Sn 比时，促进了非晶态 Si 壳的沉积。
