Department of Mechanical and Control Engineering, Graduate School of Science and Engineering, Tokyo Institute of Technology, Tokyo, Japan.
Nanotechnology. 2011 Jul 29;22(30):305605. doi: 10.1088/0957-4484/22/30/305605. Epub 2011 Jun 28.
Silicon nanocrystals have recently attracted significant attention for applications in electronics, optoelectronics, and biological imaging due to their size-dependent optical and electronic properties. Here a method for synthesizing luminescent silicon nanocrystals from silicon tetrachloride with a nonthermal plasma is described. Silicon nanocrystals with mean diameters of 3-15 nm are synthesized and have a narrow size distribution with the standard deviation being less than 20% of the mean size. Control over crystallinity is achieved for plasma pressures of 1-12 Torr and hydrogen gas concentrations of 5-70% through adjustment of the plasma power. The size of nanocrystals, and resulting optical properties, is mainly dependent on the gas residence time in the plasma region. Additionally the surface of the nanocrystals is covered by both hydrogen and chlorine. Oxidation of the nanocrystals, which is found to follow the Cabrera-Mott mechanism under ambient conditions, is significantly faster than hydrogen terminated silicon due to partial termination of the nanocrystal surface by chlorine.
硅纳米晶体由于其尺寸依赖的光学和电子特性，最近在电子学、光电学和生物成像等领域引起了极大的关注。这里描述了一种使用非热等离子体从四氯化硅合成发光硅纳米晶体的方法。合成了平均直径为 3-15nm 的硅纳米晶体，具有较窄的尺寸分布，标准偏差小于平均尺寸的 20%。通过调整等离子体功率，可以在 1-12 托和 5-70%的氢气浓度的等离子体压力下实现对晶体的控制。纳米晶体的尺寸以及由此产生的光学性质主要取决于气体在等离子体区域中的停留时间。此外，纳米晶体的表面同时覆盖着氢和氯。在环境条件下，纳米晶体的氧化遵循卡伯拉-莫特机制，由于纳米晶表面部分被氯终止，其氧化速度明显快于氢终止的硅。
