纳米ZnO基紫外探测器的制备与性能研究

发布时间：2018-06-15 02:52

本文选题：紫外探测器 + ZnO纳米棒阵列　；参考：《浙江大学》2015年硕士论文

【摘要】：紫外探测技术是一项新型军民两用技术,在空间通讯、污染监测、导弹羽焰探测以及生物医学领域都有着广泛的应用。相比于传统的商用光电倍增管和硅基紫外探测器,基于第三代宽禁带半导体材料的紫外探测器可避免使用复杂昂贵的滤光片,并且工作时无需冷却即可实现对紫外线的探测,因此近来得到了人们的青睐。在众多宽禁带半导体材料中,一维氧化锌(ZnO)纳米材料具有物理化学性质稳定、耐辐射、比表面积大、载流子迁移率高、制备方法简单以及环境友好等特点,被认为是理想的紫外探测材料之一。但一维ZnO纳米材料中存在较多的表面态和缺陷,易形成各类陷阱中心,导致纳米ZnO基紫外探测器性能较差,限制了其实际应用。为了制备探测灵敏度高,响应速度快的纳米ZnO基紫外探测器,本文从材料设计和结构设计两方面入手,优化纳米ZnO基紫外探测器的性能。一方面,采用水热法,通过掺杂不同元素(Cu、Sb),制备了ZnO基纳米棒(薄膜)阵列,并在此基础上分别制备了Cu掺杂的ZnO纳米薄膜紫外探测器和Sb掺杂的ZnO同质结紫外探测器；另一方面,首次采用光化学沉积法制备了p-NiO/n-ZnO异质结紫外探测器,并对材料的生长机理及紫外探测器的性能做了深入研究。具体研究内容如下：1、采用水热法和后续退火工艺制备了Cu掺杂ZnO纳米薄膜基紫外探测器,研究了Cu掺杂对ZnO纳米棒阵列的形貌以及紫外探测性能的影响,发现Cu掺入后,ZnO纳米棒的长径比明显降低,且随着掺杂浓度的增加,出现了从纳米棒逐渐向薄膜转变的趋势；与未掺杂的ZnO纳米棒阵列比较,Cu掺入后,紫外探测性能明显提高,这主要归因于掺入Cu引起的相关复合缺陷对电子的捕获和去捕获作用。2、通过低温水热工艺制备了Sb掺杂的p型ZnO纳米棒阵列,并在FTO衬底上制备了p-Sb:ZnO/n-ZnO同质结纳米棒阵列紫外探测器。采用X射线光电子能谱和二次离子质谱分析法证明了Sb的存在,电流-电压曲线显示出明显的整流特性,且制备的同质p-n结纳米棒阵列紫外探测器具有高达3300%的探测灵敏度和较快的响应速度。3、在上述工作的基础上,首次采用光化学沉积法制备了蜂窝状的p-NiO/n-ZnO异质结紫外探测器,通过改变生长条件调控形貌和器件的性能。研究现,蜂窝状NiO纳米结构的形成与光化学沉积过程中ZnO纳米棒阵列附近产生的OH-离子有关。制备的p-NiO/n-ZnO异质结具有明显的整流特性,开启电压只有0.66 V,在365 nm紫外光照射下具有较高的灵敏度和较快的响应速度,明显优于ZnO纳米棒阵列紫外探测器。NiO蜂窝状的特殊形貌以及NiO和ZnO界面处形成的空间电荷区两者共同作用,提高了探测器的性能。
[Abstract]:Ultraviolet detection technology is a new dual-use technology, which is widely used in space communication, pollution monitoring, missile plume detection and biomedicine. Compared with traditional commercial photomultiplier tubes and silicon based UV detectors, ultraviolet detectors based on the third generation wide band gap semiconductor materials can avoid the use of complex and expensive filters, and can detect ultraviolet rays without cooling. As a result, people have recently been in favor of it. Among the wide band gap semiconductor materials, one-dimensional zinc oxide (ZnO) nanomaterials are characterized by stable physical and chemical properties, strong radiation resistance, large specific surface area, high carrier mobility, simple preparation methods and environmentally friendly preparation. It is considered to be one of the ideal ultraviolet detection materials. However, there are many surface states and defects in one-dimensional ZnO nanomaterials, which are easy to form various trap centers, which leads to the poor performance of nano-ZnO based UV detectors, which limits their practical application. In order to prepare nanocrystalline ZnO based UV detectors with high detection sensitivity and high response speed, the performance of nanocrystalline ZnO based UV detectors was optimized from two aspects: material design and structure design. On the one hand, ZnO nanorods (thin film) arrays were prepared by hydrothermal method, and Cu-based nanorods (thin film) arrays were prepared by doping different elements, and Cu-doped ZnO thin film UV detectors and SB doped ZnO homojunction UV detectors were prepared respectively. On the other hand, p-NiO / n-ZnO heterojunction UV detectors were prepared by photochemical deposition for the first time. The specific research contents are as follows: 1. Cu-doped ZnO nanocrystalline UV detectors were prepared by hydrothermal method and subsequent annealing process. The effects of Cu doping on the morphology and UV detection properties of ZnO nanorod arrays were studied. It was found that the aspect ratio of ZnO nanorods decreased obviously with Cu doping, and with the increase of doping concentration, the nanorods changed from nanorods to thin films, and the UV detection performance of ZnO nanorods doped with Cu was improved compared with that of undoped ZnO nanorod arrays. This is mainly due to the electron capture and detrapping effect of the related composite defects caused by Cu doping. Sb-doped p-type ZnO nanorod arrays were prepared by hydrothermal process at low temperature. The p-Sb: ZnO / n-ZnO nanorods array UV detectors were fabricated on FTO substrates. The existence of SB was proved by X-ray photoelectron spectroscopy and secondary ion mass spectrometry, and the current-voltage curve showed obvious rectifying characteristics. The homogenous p-n junction nanorod array UV detector has a high detection sensitivity of 3300% and a fast response rate of .3.Based on the above work, the honeycomb p-NiO / n-ZnO heterojunction UV detector was prepared by photochemical deposition for the first time. The morphology and the performance of the device were controlled by changing the growth conditions. The formation of honeycomb nio nanostructures is related to the OH- ions produced near ZnO nanorod arrays during photochemical deposition. The p-NiO / n-ZnO heterojunction has the characteristic of rectifying, the switching voltage is only 0.66 V, and it has higher sensitivity and faster response speed under 365 nm UV irradiation. It is better than ZnO nanorod array UV detector. Nio honeycomb shape and the space charge region formed at the interface between nio and ZnO. The performance of the detector is improved.
【学位授予单位】：浙江大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN23

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