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arXiv 0811.3525cond-mat.mtrl-sci
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氧化物辅助无催化剂合成氮化硅纳米线的动力学研究

Kinetic study of the oxide-assisted catalyst-free synthesis of silicon nitride nanowires

J. Farjas, A. Pinyol, Chandana Rath, P. Roura, E. Bertran

摘要:

报道了在1200-1440 ℃温度范围内,由硅纳米颗粒与N2反应合成Si_3N_4纳米线。氮化条件使得通过颗粒中氧化硅的存在和通过硅在没有催化剂的情况下的活性氧化来促进与氮的反应。结果表明,Si到Si 3 N4的转化率取决于实验中使用的硅颗粒的量,并且通常,对于更大的量,反应减慢。这种趋势是由颗粒堆积造成的,颗粒堆积限制了炉内气氛和内部颗粒周围气氛之间的气体交换。在第一阶段中,局部氧分压在内部颗粒周围增加并局部抑制氮化。如果反应物Si纳米颗粒的量足够小,则避免了这种外在效应,并且可以测量本征氮化动力学。实验表明,本征动力学不依赖于温度。

英文摘要:

The synthesis of Si3N4 nanowires from the reaction of silicon nanoparticles with N2 in the 1200-1440 C temperature range is reported. The nitridation conditions are such that the reaction with nitrogen is favoured by the presence of silicon oxide in the particles and by the active oxidation of silicon without a catalyst. It is shown that the Si to Si3N4 conversion rate depends on the amount of silicon particles used in the experiments and that, in general, the reaction slows down for greater amounts. This trend is explained by particle stacking, which restricts the exchange of gases between the furnace atmosphere and the atmosphere around the inner particles. In a first stage, local oxygen partial pressure increases around the inner particles and inhibits nitridation locally. If the amount of reactant Si nanoparticles is small enough, this extrinsic effect is avoided and the intrinsic nitridation kinetics can be measured. Experiments show that intrinsic kinetics does not depend on temperature.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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