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Exploitation of spontaneous formation of nano-structures through nonlinear chemical dynamics

通过非线性化学动力学开发纳米结构的自发形成

基本信息

批准号：
14350454
负责人：
NAKATO Yoshihiro
金额：
$ 9.6万
依托单位：
OSAKA UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2002
资助国家：
日本
起止时间：
2002 至 2003
项目状态：
已结题

项目摘要

We have studied spontaneous formation of nano-structures through non-equilibrium nonlinear dynamics for the purpose of exploitation and establishment of a new method for nano-structuring, and obtained the following results : (1)Scratching of H-terminated vicinal Si(111) surfaces with Teflon tweezers in 40% NH_4F led to formation of nano-wires, mainly composed of carbon and fluorine. The successive etching of the Si(111) surfaces with the nano-wires in 40% NH_4F produced surprisingly well-ordered step structures on Si(111). (2)Immersion of H-terminated Si(111) surfaces in aqueous hydrogen halide (HX) solutions caused halogenation of the Si(111) surface (i.e. conversion of surface Si-H bonds to Si-X bonds). The reactions depended largely on experimental conditions such as the kind of hydrogen halide, the presence or absence of dissolved oxygen, and reaction time. (3)The immersion of H-terminated Si(111) in 7.1 M HI at 5℃ produced oriented nano-wires at the surface. High-resolution XPS measurements showed that the nano-wires were composed of silicon iodides or related compounds. The orientation of the nano-wires was explained to arise from the fact that the wires formation occurred under a surface-diffusion limited condition. (4)The shape and size of metal nano-particles could be regulated by photo and electric-field assisted chemical processes. (5)Photo-etching of TiO_2 (rutile) in aq. H_2SO_4 produced ordered rectangular nano-holes and grooves in the <001> direction. (6)The appearance mechanisms for a number of electrochemical oscillations and accompanying spatiotemporal patterns were revealed.

为了探索和建立一种新的纳米结构化方法，我们采用非平衡非线性动力学方法研究了纳米结构的自发形成，得到了以下结果：（1）在40%NH_4F溶液中，用Teflon镊子对H端Si（111）邻位表面进行剪切，形成了主要由碳和氟组成的纳米线。在40%NH_4F溶液中连续刻蚀Si（111）表面，在Si（111）表面形成了有序的台阶结构。（2）H封端的Si（111）表面在卤化氢（HX）水溶液中的浸泡导致了Si（111）表面的卤化（即表面Si-H键转化为Si-X键）。反应在很大程度上取决于实验条件，如卤化氢的种类，溶解氧的存在或不存在，以及反应时间。（3）在5℃的7.1M HI溶液中浸泡H端Si（111），在表面形成了取向的纳米线。高分辨率XPS测量表明，纳米线由碘化硅或相关化合物组成。纳米线的取向被解释为产生的事实，即线的形成下发生的表面扩散限制条件。（4）光、电场辅助化学过程可以调控金属纳米粒子的形状和尺寸。（5）TiO_2（金红石型）在水溶液中的光刻。H_2SO_4在纳米孔表面形成了有序的矩形纳米孔和沟槽<001>。（6）揭示了一系列电化学振荡现象的出现机制及其伴随的时空模式。