Synthesis and oxidation of luminescent silicon nanocrystals from silicon tetrachloride by very high frequency nonthermal plasma
Synthesis and oxidation of luminescent silicon nanocrystals from silicon tetrachloride by very high frequency nonthermal plasma
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DOI：
10.1088/0957-4484/22/30/305605
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发表时间：
2011-07-29
期刊：
影响因子：
3.5
通讯作者：
Okazaki, Ken
中科院分区：
文献类型：
--
作者：
Gresback, Ryan;Nozaki, Tomohiro;Okazaki, Ken
硅纳米晶体由于其尺寸依赖的光学和电子性质，最近在电子学、光电子学和生物成像领域的应用引起了人们的极大关注。本文介绍了一种用低温等离子体从四氯化硅合成发光硅纳米晶的方法。合成了平均粒径为3-15 nm的硅纳米晶，并且具有窄的尺寸分布，标准偏差小于平均尺寸的20%。通过调节等离子体功率，在1-12托的等离子体压力和5-70%的氢气浓度下实现对结晶度的控制。纳米晶体的尺寸和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，纳米晶体的表面被氢和氯覆盖。氧化的纳米晶体，这是发现遵循Cabrera-莫特机制在环境条件下，是显着快于氢封端的硅，由于部分终止的表面由氯。
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.