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Formation process of surface hydrogenated Si nanocrystallites and its optical properties.

表面氢化硅纳米晶的形成过程及其光学性质。

基本信息

批准号：
16560018
负责人：
UMEZU Ikurou
金额：
$ 2.3万
依托单位：
Konan University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2004
资助国家：
日本
起止时间：
2004 至 2006
项目状态：
已结题

项目摘要

Formation process of surface hydrogenated Si nancrystallites by pulsed laser ablation in hydrogen gas and properties of deposited material are clarified in this research. The deposit prepared by this method consists of nanocrystalline primary structure and aggregated secondary structures. The size of primary structure is insensitive to the background gas pressure, while the structure of secondary structure depends on the background gas pressure. From the analysis of the fractal structure, it is clarified that correlation between plume size and substrate-target distance determines the secondary structure. Hydrogen gas pressure acts as parameter to control the plume size. When the plume size is smaller than the substrate target distance, cluster-cluster aggregation in the plume results in fiber like aggregated secondary structure. This result indicates that the aggregated secondary structure can be controlled by the plume size though the hydrogen gas pressure. The nanocrystallites are not an alloy of silicon and hydrogen but are surface hydrogenated silicon nanocrystal. This means that the hydrogenation takes place after the formation of the nanocrystal. The temperature to stabilize Si-H bond is lower than the melting point of the silicon nanocrystal. Therefore, hydrogenation starts after the formation of the nanocrystallites. Eventually, the Si-H bonds are stabilized on the surface. The porosity of the hydrogenated sample is larger than that of the nonhydrogenated one. This is because surface hydrogenated nanocrystal prevent aggregation. The optical band gap of the surface hydrogenated sample is larger than that of nonhydrogenated one. This band gap shift corresponds to the porosity of the sample. The surface hydrogenation stabilizes the surface and reduces the interaction between the nanocystallites. The pulsed laser ablation of silicon in hydrogen gas is a promising method to control the secondary structure and optical properties of the material.

本研究阐明了氢气中脉冲激光烧蚀表面氢化硅纳米晶的形成过程和沉积材料的性质。该方法制备的存款由纳米晶的初级结构和聚集的二级结构组成。一级结构的大小对背景气压不敏感，而二级结构的大小取决于背景气压。从分形结构的分析，阐明了羽流的大小和衬底-靶距离的相关性决定了二级结构。氢气压力作为控制羽流尺寸的参数。当羽流尺寸小于衬底靶距时，羽流中团簇-团簇聚集导致纤维状聚集二级结构。这一结果表明，聚集的二级结构可以通过氢气压力的羽流的大小来控制。纳米晶不是硅和氢的合金，而是表面氢化的硅纳米晶。这意味着氢化发生在生成氢化物之后。稳定Si-H键的温度低于硅溶胶的熔点。因此，氢化在纳米晶形成之后开始。最终，Si-H键稳定在表面上。氢化样品的孔隙率大于未氢化样品的孔隙率。这是因为表面氢化的α-淀粉阻止了聚集。表面氢化样品的光学带隙比未氢化样品的光学带隙大。该带隙偏移对应于样品的孔隙率。表面氢化稳定了表面并减少了纳米晶体之间的相互作用。氢气中的脉冲激光烧蚀硅是一种很有前途的控制材料二次结构和光学性质的方法。

项目成果

期刊论文数量（68）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

Preparation of surface controlled silicon nanocrystallites by pulsed laser ablation

脉冲激光烧蚀制备表面控制硅纳米晶

DOI：
发表时间：
2005
期刊：
The Proceedings of the 27th International Conference on the Physics of Semiconductors
影响因子：
0
作者：
I.UMEZU;M.Inada;T.Makino;A.Sugimura
通讯作者：
A.Sugimura

Temperature dependence of time-resolved luminescence spectra for ID excitons in single-walled carbon nanotubes in micelles.

胶束中单壁碳纳米管中 ID 激子的时间分辨发光光谱的温度依赖性。