Cu衬底上超细ZnO纳米线的制备及其光学性质研究

发布时间：2018-04-13 11:56

本文选题：超细ZnO纳米线 + 光致发光　；参考：《哈尔滨师范大学》2015年硕士论文

【摘要】：氧化锌(ZnO)是现今非常重要的宽禁带半导体材料,禁带宽度大约是3.37 eV。由于其在室温下具有高达60 meV的激子束缚能,因此其在紫外光电器等方面有很大的应用潜力。与大尺寸的纳米结构相比,超小纳米结构由于具有相当大的比表面积,已经成为纳米科学和纳米技术领域一个重要的研究课题。近年来,Ag,Au,ZnS,Si,CdSe和Fe3O4等超细纳米材料的合成已经成为研究热点,关于这些材料的一些重大突破综述近期也被报道。在纳米材料研究领域,一维纳米级半导体由于在电子、光子、传感器、光催化、能量产生(比如太阳能电池)、场发射器件等方面具有潜在的应用而备受关注。ZnO是最受关注的纳米材料之一。通常,直径小于10 nm的ZnO纳米线由于其量子限域效应明显,能展现出神奇和独特的性质。故而研究超细ZnO纳米线的制备及其相应的物理和化学性质也吸引了很多课题小组的兴趣。光致发光光谱是不与材料直接接触且不损坏材料的探测材料内部结构的非常有效的途径。因此本文针对当前纳米材料领域仍然比较热点的材料ZnO进行了深入的研究,包括超小尺寸ZnO纳米结构的制备及其光学性质。本文用化学气相沉积(CVD)方法在Cu衬底上制备了超细的ZnO纳米线,利用扫描电子显微镜(SEM)和透射电子显微镜(TEM)对其表面形貌进行了表征,并对其进行了光致发光测试。由TEM平面图可知,本文所制备的ZnO纳米线的直径为5 nm~8 nm。本文开辟了一种不用催化剂就能得到超细一维纳米结构的途径(CVD方法)。本文使用325 nm He-Cd激光器对所制备的超细ZnO纳米线进行了光致发光性质研究。在室温下,超细ZnO纳米线PL光谱的自由激子峰位比ZnO粉末的蓝移了40 meV,这被归因于纳米线的量子限域效应。室温PL光谱的深能级发射峰(450nm~650 nm)强度很高,这是由于小尺寸所导致的材料内部缺陷。通过将合成样品在15 K下的光致发光测试(PL)结果与已有文献中直径为4.1 nm的ZnO纳米线在相同温度(15 K)下的PL测试结果进行了对比,本文进一步证实了:纳米线的量子限域效应会导致自由激子(FX)峰位的蓝移,且纳米线的直径越小,FX峰位的蓝移效果越明显。为了验证中心位于3.322 eV(标志为FX-LO)的峰位的本质,文中展示了随着温度升高,样品光致发光光谱的变化情况。本文还利用法国J-Y公司生产的HR800微区拉曼系统对样品进行了拉曼测试,其激发光源488 nm的氩离子激光器,所测拉曼光谱表明ZnO的小尺寸会导致拉曼峰的频移和非对称加宽。由于这种超细一维纳米结构是在Cu衬底上制备的,与其他的半导体或绝缘体衬底相比,更利于人们对超细一维纳米结构的研究和应用。这种ZnO微观结构将在电子学和光学方面有深远的应用影响。
[Abstract]:Zinc oxide (ZnO) is a very important wide band gap semiconductor material with a band gap of about 3.37 EV.Due to its exciton binding energy of up to 60 meV at room temperature, it has great application potential in ultraviolet light appliances and so on.Compared with large size nanostructures, ultrasmall nanostructures have become an important research topic in nanoscience and nanotechnology due to their large specific surface area.In recent years, the synthesis of ultrafine nanomaterials, such as Fe3O4 and Fe3O4, has become a hot topic, and some important breakthroughs in these materials have been reported recently.In the field of nanomaterials, one-dimensional nanoscale semiconductors, due to the effects of electrons, photons, sensors, photocatalysis,Energy generation (such as solar cells, field emission devices and other potential applications) has attracted much attention. ZnO is one of the most concerned nanomaterials.In general, ZnO nanowires with diameter less than 10 nm can exhibit magical and unique properties because of their obvious quantum limiting effect.Therefore, the preparation of ultrafine ZnO nanowires and their corresponding physical and chemical properties have attracted the interest of many research groups.Photoluminescence spectroscopy is a very effective way to detect the internal structure of materials without direct contact with and without damaging the materials.Therefore, in this paper, the preparation and optical properties of ultrasmall ZnO nanostructures have been studied in detail, which is still a hot material in the field of nanomaterials.Ultrafine ZnO nanowires were prepared on Cu substrates by chemical vapor deposition (CVD) method. The surface morphology was characterized by scanning electron microscopy (SEM) and transmission electron microscope (TEM), and photoluminescence (PL) was measured.According to the TEM plan, the diameter of the ZnO nanowires prepared in this paper is 5 nm~8 nm.In this paper, a new way to obtain ultrafine one-dimensional nanostructures without catalyst has been developed by chemical vapor deposition (CVD).The photoluminescence properties of ultrafine ZnO nanowires prepared by 325 nm He-Cd laser have been studied.At room temperature, the peak position of free excitons in PL spectra of ultrafine ZnO nanowires is 40 MEV bluer than that of ZnO powders, which is attributed to the quantum limiting effect of nanowires.The deep level emission peak at room temperature PL spectra of 450 nm ~ 650 nm) is very high, which is due to the internal defects of the material due to the small size.The photoluminescence (PL) results of the synthesized samples at 15 K were compared with those of ZnO nanowires with a diameter of 4.1 nm at the same temperature of 15 K.It is further proved that the quantum limiting effect of nanowires will lead to the blue shift of the free exciton FX peak position, and the smaller the diameter of nanowires is, the more obvious the blue shift effect of FX peak position will be.In order to verify the nature of the peak located at 3.322 EV (marked FX-LOO), the changes of photoluminescence spectra of the samples with the increase of temperature are shown in this paper.The Raman measurements of the samples were also carried out by using the HR800 micro-region Raman system produced by J-Y company in France. The Raman spectra of the laser excited at 488nm show that the small size of the ZnO leads to the frequency shift and asymmetric broadening of the Raman peaks.Compared with other semiconductor or insulator substrates, this ultrafine one-dimensional nanostructure is more suitable for the research and application of ultrafine one-dimensional nanostructures.The microstructure of ZnO will have a profound effect on electronics and optics.
【学位授予单位】：哈尔滨师范大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN304.21

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