宏观树枝状铜纳米线的制备及分形学研究

Synthesis of the Macroscopic Dentritic Copper Nanowires and Fractal Research

为了进一步揭示固态离子学方法制备铜纳米线的生长机理,选取具有高离子电导率的快离子导体Rb_4Cu_(16)Cl_(13)I_7薄膜,利用固态离子学方法在外加恒定电流3μA作用下,制备厘米级铜纳米线.采用扫描电子显微镜对其微观形貌进行了表征和分析,利用能量色散光谱仪确定纳米线的化学成分.结果表明:制备的铜纳米线呈现宏观树枝状结构,在靠近阴极位置整齐排布,长度约为2 mm,且排布比较紧密,部分纳米线在生长过程中出现分形生长,最长分支长度约为1 cm,排布比较稀疏;铜纳米线呈长程无序短程有序,直径分布范围为90~100 nm,纳米线表面铜纳米颗粒直径分布范围为10~20 nm,树枝状铜纳米线的分形维数为1.35,说明树枝状铜纳米线较少,铜纳米线的生长机理分析表明,树枝状结构的出现与纳米线"顶端生长优势"有关.

In order to reveal the growth mechanism of copper nanowires prepared by a solid-state ionics method furtherly,copper nanowires with centimeter grade were prepared by a solid-state ionics method using fast ionic conductor Rb4Cu16Cl13I7 films under 3 μA direct current electric field. The surface morphology of the copper nanowires was characterized and analysed by scanning electron microscopy,and the chemical composition of the nanowires was measured by energy dispersive spectrometer. The results show the prepared copper nanowires are dendritic structures macroscopicly,which are arranged neatly near the cathode and the length is about 2 mm.Besides,the results indicate that the copper nanowires arrange sparsely,and the fractal growth occurs in the growth process of some nanowires whose longest branch length is about 1 cm. Copper nanowires present long-range disorder and short-range order,the diameters of nanowires range from 90 to 100 nm,the diameters of copper nanoparticles on the nanowires range from 10 to 20 nm. The fractal dimension of dentritic copper nanowires is 1.35,which indicates that there are less dentritic nanostructures in the whole growing nanostructures. The growth mechanism of copper nanowires is associated with apical growth advantage.