CdS超晶格納米線與超長碳線的制備與性質(zhì)研究
發(fā)布時間：2019-03-13 10:49
【摘要】：CdS具有較好的光學特性與優(yōu)異的光電轉(zhuǎn)換特性，在光電器件領域具有重要的應用價值。本文通過化學氣相沉積法合成了基于Sn元素的CdS超晶格納米線，并采用元素mapping與EDS能譜分析，表明我們所生成的納米線是由外層CdS殼層與內(nèi)層間斷性分布的Sn段組成的一種具有超晶格結構的納米線。為了研究這種納米線的熒光特性與光傳導模式，通過改變激發(fā)波長、溫度等方法，發(fā)現(xiàn)Sn的存在使得CdS晶格收到擠壓作用，導致原子之間相互作用加強，帶隙增大，隨著溫度的降低，這一現(xiàn)象可以被明顯的觀察到。CdS納米線的外表面由帶隙發(fā)光起主要作用，內(nèi)部光學腔中則由束縛態(tài)深能級發(fā)光為主。除此之外，隨著溫度的降低，由于聲子漲落收到抑制，帶隙發(fā)光出現(xiàn)藍移，但是束縛態(tài)發(fā)光峰的峰位基本不變，這是由于束縛態(tài)發(fā)光主要依賴于納米線表面結晶度，，表面缺陷決定了束縛態(tài)能級對載流子的捕獲能力。隨著激發(fā)功率的增加，納米線中束縛態(tài)發(fā)光逐漸飽和，這時我們觀察到帶隙發(fā)光出現(xiàn)了明顯的增強，隨后我們通過泵浦光在CdS納米線中實現(xiàn)了lasing，證明CdS納米線內(nèi)部具有良好的F-P腔結構，在制造微激光器方面有重要的應用價值。 本文以固體石墨粉末為碳源，通過化學氣相沉積法實現(xiàn)了微米量級直徑的超長超直碳線的一步可控合成。長徑比超過1000:1的碳線沿著氣流流動方向平行生長于反應粉末表面。相對于傳統(tǒng)的一維碳材料的利用氣體碳源的生長方式，本文所生成的碳線無論從制備過程上還是尺寸結構上都具有與眾不同的特性。隨后利用SEM、TEM、EDS并結合XRD與拉曼光譜等方法表征了碳線的結構特性，發(fā)現(xiàn)所生成的碳線是一種外部多層石墨結構的碳原子層包裹內(nèi)部硅芯的結構，綜合表征得到的結構我們分析了所生成的碳線的生長機理以及硅在反應中起到的作用。最后我們探究了做生成的碳線的相關電學性質(zhì)，其優(yōu)于石墨的導電率和相對穩(wěn)定的熔斷電壓使得這種新型的超長超直碳線在微電路與微電學期間有重要的應用價值。
[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.
【學位授予單位】：北京理工大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：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.
【學位授予單位】：北京理工大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：TB383.1
【參考文獻】
相關期刊論文 前2條
1 閆國慶;李旦;張立歡;趙博文;符秀麗;高e
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