CdS超晶格纳米线与超长碳线的制备与性质研究
发布时间：2019-03-13 10:49
【摘要】：CdS具有较好的光学特性与优异的光电转换特性，在光电器件领域具有重要的应用价值。本文通过化学气相沉积法合成了基于Sn元素的CdS超晶格纳米线，并采用元素mapping与EDS能谱分析，表明我们所生成的纳米线是由外层CdS壳层与内层间断性分布的Sn段组成的一种具有超晶格结构的纳米线。为了研究这种纳米线的荧光特性与光传导模式，通过改变激发波长、温度等方法，发现Sn的存在使得CdS晶格收到挤压作用，导致原子之间相互作用加强，带隙增大，随着温度的降低，这一现象可以被明显的观察到。CdS纳米线的外表面由带隙发光起主要作用，内部光学腔中则由束缚态深能级发光为主。除此之外，随着温度的降低，由于声子涨落收到抑制，带隙发光出现蓝移，但是束缚态发光峰的峰位基本不变，这是由于束缚态发光主要依赖于纳米线表面结晶度，，表面缺陷决定了束缚态能级对载流子的捕获能力。随着激发功率的增加，纳米线中束缚态发光逐渐饱和，这时我们观察到带隙发光出现了明显的增强，随后我们通过泵浦光在CdS纳米线中实现了lasing，证明CdS纳米线内部具有良好的F-P腔结构，在制造微激光器方面有重要的应用价值。 本文以固体石墨粉末为碳源，通过化学气相沉积法实现了微米量级直径的超长超直碳线的一步可控合成。长径比超过1000:1的碳线沿着气流流动方向平行生长于反应粉末表面。相对于传统的一维碳材料的利用气体碳源的生长方式，本文所生成的碳线无论从制备过程上还是尺寸结构上都具有与众不同的特性。随后利用SEM、TEM、EDS并结合XRD与拉曼光谱等方法表征了碳线的结构特性，发现所生成的碳线是一种外部多层石墨结构的碳原子层包裹内部硅芯的结构，综合表征得到的结构我们分析了所生成的碳线的生长机理以及硅在反应中起到的作用。最后我们探究了做生成的碳线的相关电学性质，其优于石墨的导电率和相对稳定的熔断电压使得这种新型的超长超直碳线在微电路与微电学期间有重要的应用价值。
[Abstract]:CdS has good optical properties and excellent photoelectric conversion characteristics, so it has important application value in the field of optoelectronic devices. In this paper, CDs superlattice nanowires based on Sn elements were synthesized by chemical vapor deposition (CVD), and analyzed by elemental mapping and EDS spectra. It is shown that the nanowires produced by us are a kind of nanowires with superlattice structure, which are composed of Sn segments with discontinuity distribution between the outer CdS shell and the inner layer. In order to study the fluorescence characteristics and light conduction mode of the nanowires, by changing the excitation wavelength and temperature, it is found that the existence of Sn causes the lattice of CdS to be squeezed, which leads to the strengthening of the interaction between atoms and the increase of the band gap. With the decrease of temperature, this phenomenon can be observed obviously. The outer surface of CDs nanowires is dominated by band gap luminescence, while the inner optical cavity is dominated by bound state deep level luminescence. In addition, with the decrease of temperature, the band gap luminescence appears blue shift due to the suppression of phonon fluctuation, but the peak position of bound state emission peak is basically unchanged, which is due to the dependence of bound state luminescence on the surface crystallinity of nanowires, and the photoluminescence of bound states is mainly dependent on the crystallinity of nanowires. Surface defects determine the trapping ability of bound-state energy levels to carriers. With the increase of the excitation power, the bound state luminescence in the nanowires gradually saturated, and then we observed that the band gap luminescence increased obviously. Then we realized the lasing, in the CdS nanowires by pumping the light. It is proved that CdS nanowires have good cavity structure and have important application value in fabricating micro-lasers. One-step controllable synthesis of ultra-long ultra-straight carbon lines with micron diameter was achieved by chemical vapor deposition using solid graphite powder as carbon source. The carbon line with a length-to-diameter ratio of more than 1000 渭 1 grows parallel to the surface of the reaction powder along the flow direction. Compared with the traditional growth mode of one-dimensional carbon materials using gas carbon source, the carbon lines produced in this paper have different characteristics both in preparation process and in size and structure. Then the structure of the carbon line was characterized by SEM,TEM,EDS and XRD and Raman spectroscopy. It was found that the carbon line formed was a kind of structure of the inner silicon core wrapped by the carbon atom layer with an outer multi-layer graphite structure. We analyzed the growth mechanism of the generated carbon line and the role of silicon in the reaction. Finally, we explore the electrical properties of the generated carbon wire, which is superior to the conductivity of graphite and the relatively stable melting voltage, which makes the new ultra-long ultra-straight carbon wire have important application value in micro-circuit and micro-electricity.
【学位授予单位】：北京理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB383.1
[Abstract]:CdS has good optical properties and excellent photoelectric conversion characteristics, so it has important application value in the field of optoelectronic devices. In this paper, CDs superlattice nanowires based on Sn elements were synthesized by chemical vapor deposition (CVD), and analyzed by elemental mapping and EDS spectra. It is shown that the nanowires produced by us are a kind of nanowires with superlattice structure, which are composed of Sn segments with discontinuity distribution between the outer CdS shell and the inner layer. In order to study the fluorescence characteristics and light conduction mode of the nanowires, by changing the excitation wavelength and temperature, it is found that the existence of Sn causes the lattice of CdS to be squeezed, which leads to the strengthening of the interaction between atoms and the increase of the band gap. With the decrease of temperature, this phenomenon can be observed obviously. The outer surface of CDs nanowires is dominated by band gap luminescence, while the inner optical cavity is dominated by bound state deep level luminescence. In addition, with the decrease of temperature, the band gap luminescence appears blue shift due to the suppression of phonon fluctuation, but the peak position of bound state emission peak is basically unchanged, which is due to the dependence of bound state luminescence on the surface crystallinity of nanowires, and the photoluminescence of bound states is mainly dependent on the crystallinity of nanowires. Surface defects determine the trapping ability of bound-state energy levels to carriers. With the increase of the excitation power, the bound state luminescence in the nanowires gradually saturated, and then we observed that the band gap luminescence increased obviously. Then we realized the lasing, in the CdS nanowires by pumping the light. It is proved that CdS nanowires have good cavity structure and have important application value in fabricating micro-lasers. One-step controllable synthesis of ultra-long ultra-straight carbon lines with micron diameter was achieved by chemical vapor deposition using solid graphite powder as carbon source. The carbon line with a length-to-diameter ratio of more than 1000 渭 1 grows parallel to the surface of the reaction powder along the flow direction. Compared with the traditional growth mode of one-dimensional carbon materials using gas carbon source, the carbon lines produced in this paper have different characteristics both in preparation process and in size and structure. Then the structure of the carbon line was characterized by SEM,TEM,EDS and XRD and Raman spectroscopy. It was found that the carbon line formed was a kind of structure of the inner silicon core wrapped by the carbon atom layer with an outer multi-layer graphite structure. We analyzed the growth mechanism of the generated carbon line and the role of silicon in the reaction. Finally, we explore the electrical properties of the generated carbon wire, which is superior to the conductivity of graphite and the relatively stable melting voltage, which makes the new ultra-long ultra-straight carbon wire have important application value in micro-circuit and micro-electricity.
【学位授予单位】：北京理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB383.1
【参考文献】
相关期刊论文 前2条
1 闫国庆;李旦;张立欢;赵博文;符秀丽;高e
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