Motility of Metal Nanoparticles in Silicon and Induced Anisotropic Silicon Etching
Motility of Metal Nanoparticles in Silicon and Induced Anisotropic Silicon Etching
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金属纳米粒子在硅中的运动性和诱导各向异性硅蚀刻
DOI：
10.1002/adfm.200800371
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发表时间：
2008-10-09
影响因子：
19
通讯作者：
Lee, Shuit-Tong
中科院分区：
文献类型：
--
作者：
Peng, Kuiqing;Lu, Aijiang;Lee, Shuit-Tong
本文系统地研究了金属颗粒在硅中的自主运动行为，以及由此产生的硅的各向异性蚀刻和硅纳米结构，特别是硅纳米线阵列在氧化氢氟酸溶液中的制备。研究发现，金属颗粒（Ag和Au）在Si中的自主运动是高度均匀的，但定向和优先沿着Si的晶体取向，而不是总是垂直于硅表面。建立了一个电动力学模型，首次令人满意地解释了硅中金属颗粒运动的微观动力学起源。根据该模型，金属颗粒表面双极性电化学反应产生的能量可以直接转化为机械功，推动金属颗粒在Si中的隧道运动。讨论了孔和丝的形成机理及其与晶体取向的关系。这些模型不仅为金属诱导的凹坑、多孔硅、硅纳米线和纳米孔的形成提供了基本的解释，还揭示了金属/硅体系中的金属颗粒可以作为自推进的纳米马达。值得注意的是，它提供了一种简便的方法来生产各种硅纳米结构，特别是从所需性能的硅晶圆上生产有序的硅纳米线阵列。
The autonomous motion behavior of metal particles in Si, and the consequential anisotropic etching of silicon and production of Si nanostructures, in particular, Si nanowire arrays in oxidizing hydrofluoric acid solution, has been systematically investigated. It is found that the autonomous motion of metal particles (Ag and Au) in Si is highly uniform, yet directional and preferential along the [100] crystallographic orientation of Si, rather than always being normal to the silicon surface. An electrokinetic model has been formulated, which, for the first time, satisfactorily explains the microscopic dynamic origin of motility of metal particles in Si. According to this model, the power generated in the bipolar electrochemical reaction at a metal particle's surface can be directly converted into mechanical work to propel the tunneling motion of metal particles in Si. The mechanism of pore and wire formation and their dependence on the crystal orientation are discussed. These models not only provide fundamental interpretation of metal‐induced formation of pits, porous silicon, and silicon nanowires and nanopores, they also reveal that metal particles in the metal/Si system could work as a self‐propelled nanomotor. Significantly, it provides a facile approach to produce various Si nanostructures, especially ordered Si nanowire arrays from Si wafers of desired properties.