【作者】 张晓光；

【导师】 袁志好；

【作者基本信息】 天津理工大学 ， 凝聚态物理， 2006， 硕士

【摘要】 一维金属纳米材料因具有新颖的物理、化学性能及在纳米器件方面重要应用价值而引起了人们广泛的兴趣。然而纳米材料器件化通常要求其制备过程具有可控性,因此纳米材料的形状控制已经引起了人们极大的关注。本工作旨在探索基于多孔氧化铝模板法来制备不同形状的金属纳米线,发展出一种能有效控制一维纳米材料形状的方法。1、我们改进了氧化铝模板的制备工艺,制备出了多种孔洞形貌各不相同的氧化铝模板:分别以硫酸和草酸作为电解液,在氧化过程中,通过缓慢改变氧化电压的方法制备出了具有梯度孔径的氧化铝模板;以草酸作为电解液,在氧化过程中按照1/ 2的系数关系改变氧化电压,得到了从一级到三级分叉结构的氧化铝模板。2、利用电化学沉积法,在以硫酸为电解液制备的具有梯度孔径的氧化铝模板中,我们合成了具有梯度直径的银纳米线和铁纳米线;在以草酸为电解液制备的具有梯度孔径的氧化铝模板中,我们合成了具有梯度直径的铋纳米线。利用扫描电子显微镜(SEM)和透射电子显微镜(TEM),我们对各种纳米线的形貌及结晶情况进行了观察和研究。结果显示:上述纳米线都具有梯度变化的直径,铁纳米线和银纳米线的直径变化范围均为12~31nm,铋纳米线的直径变化范围为11~55nm;银纳米线和铋纳米线具有单晶结构,而铁纳米则为多晶结构。3、利用电化学沉积法,我们在具有多级分叉结构的模板中生长了不同形状铁纳米线——Y型铁纳米线,枝状结构的铁纳米线。利用选区电子衍射(SAED)和高分辨透射电子显微镜(HRTEM)对这些纳米线进行了研究,结果显示:在这些纳米线的主干上是α-Fe单晶,而在细小的分支上铁是多晶结构。更多还原

【Abstract】 One-dimensional nanomaterials have received considerable attention over the past decade because of their novel physical and chemical properties and potential applications in future nanodevices. It is well known, however, that the property of nanomaterials is heavy dependent with its shape, so how to control the shape of nanomaterials becomes a hot topic in material research field at present. As one of the useful means in the shape control of one-dimensional nanomaterials, anodic alum -inum oxide (AAO) templates have received widely attention. In this paper, we pay considerable attention to the shape controlling of metal nanowires based on AAO templates, and then develop the template-synthesis method for fabricating nanowires with different shapes.1)We have extended the functions of the AAO template to fabricate graded and multi-branched nanochannels. The AAO template with a graded pore diameter was prepared through gradually changing the anodic voltage during an anodization in 0.3M sulfuric acid or oxalic acid. While the AAO templates with various branched pores were prepared through one- to multi-step varying the anodic voltage by a factor of 1/ 2 during an anodization of aluminum in 0.3M oxalic acid.2)Based on the templates with a graded pore diameter, several graded metal nanowires (i.e. Ag, Fe, and Bi) were achieved by electrochemical deposition. SEM and TEM were used to characterize these nanowires. The results show that these nanowires have obvious graded diameters along the nanowire direction with gradient ranging from about 12 to 31nm for Ag and Fe, and from about 11 to 55nm for Bi. Their high-resolution TEM images show that Ag nanowires and Bi nanowires have single-crystalline structure, and Fe nanowire has polycrystalline structure.3)The corresponding multi-branched Fe nanowires were achieved by electrodepositing Fe into the branched pores of the AAO template used. Selecting area electron diffraction and high-resolution TEM images show that these branched Fe nanowires have a single-crystalline stem with a body-centered cubic lattice and polycrystalline branches.更多还原