半导体金属氧化物传感器的制备与性能研究

发布时间：2018-06-03 05:46

本文选题：气体传感器 + p-Co_3O_4/n-SnO_2　；参考：《西南交通大学》2017年硕士论文

【摘要】：近年来,随着人民生活水平的提高以及对环保的日益重视,人们对各种有毒、有害气体的检测提出了更高的要求。基于金属氧化物的半导体型气体传感器因具有较低的成本和优异的气敏特性成为气体传感器领域的研究热点。气体传感器的气敏性能取决于传感材料的结构特性。因此制备高性能气敏材料一直是半导体气体传感器的研究重点和难点。本论文以合成出高性能的气敏材料为研究目标,通过调控气敏材料的形貌结构来对其气敏性能进行了研究。主要研究内容如下:(1)利用p-n异质结的界面协同效应来调节气敏材料的气敏选择性。本文首先采用操作简单的浸泡煅烧法制备了不同Co/Sn摩尔比的p-Co_3O_4/n-SnO_2 p-n异质结复合材料,并对其气敏性能进行了系统研究。实验结果表明,该p-Co_3O_4/n-SnO_2复合气敏材料对典型还原气体如CO,H_2S和NH_3显示为n型气敏响应,对H_2则表现出独特的p型响应。我们将该独特的气敏响应反转行为归结于p-Co_3O_4/n-SnO_2异质结中SnO_2和Co_3O_4对还原气体具有不同的气敏反应活性而导致的势垒高度调制有关。该研究工作证明,利用异质结材料对目标气体的不对称气体反应活性可以实现调节p-n异质结势垒高度的调节,为复合气敏材料气敏特性的优化提供了重要的理论支撑。(2)研究了不同形貌Ag_3PO_4纳米材料的室温NH_3气敏性能。目前关于Ag_3PO_4作为光催化剂的相关报道较多,而对将其作为气敏材料用于气体检测还鲜有报道。我们利用离子交换法和固相研磨法制备出了纳米管和纳米颗粒两种不同形貌Ag_3PO_4纳米材料,并研究了形貌对其NH_3室温气敏性能的影响。气敏性能测试结果表明,相较于Ag_3PO_4纳米颗粒,Ag_3PO_4纳米管具有更加优异的气敏特性,在室温下对NH_3具有更高的灵敏度和选择性,检测限可低至1Oppm。该工作对研究Ag_3PO_4的室温气敏机理以及形貌对其气敏反应活性的影响规律奠定了基础。
[Abstract]:In recent years, with the improvement of people's living standards and the increasing attention to environmental protection, people put forward higher requirements for the detection of various toxic and harmful gases. Semiconductor gas sensor based on metal oxide has become a research hotspot in the field of gas sensor because of its low cost and excellent gas sensitivity. The gas sensing performance of the gas sensor depends on the structure of the sensing material. Therefore, the preparation of high-performance gas-sensitive materials has been the focus and difficulty of semiconductor gas sensors. The aim of this thesis is to synthesize high performance gas sensing materials and to study their gas sensing properties by adjusting the morphology and structure of the gas sensing materials. The main contents of this study are as follows: (1) the gas sensing selectivity of gas sensing materials is regulated by the interface synergy of p-n heterojunction. In this paper, p-Co_3O_4/n-SnO_2 p-n heterojunction composites with different Co/Sn molar ratios were prepared by a simple soaking and calcination method, and their gas-sensing properties were systematically studied. The experimental results show that the p-Co_3O_4/n-SnO_2 composite gas sensing material exhibits n-type gas sensing response to typical reductive gases such as COG / H _ 2S and NH_3, and a unique p-type response to H _ (2). We attribute this unique gas sensing response inversion behavior to the barrier height modulation of SnO_2 and Co_3O_4 in p-Co_3O_4/n-SnO_2 heterostructures due to their different gas-sensing reactivity to reducing gases. It is proved that the potential barrier height of p-n heterojunction can be adjusted by using the asymmetric gas reaction activity of the heterojunction material to the target gas. It provides an important theoretical support for the optimization of gas-sensing properties of composite gas-sensing materials. (2) the room-temperature NH_3 gas-sensing properties of Ag_3PO_4 nanomaterials with different morphologies are studied. At present, there are many reports about Ag_3PO_4 as photocatalyst, but there are few reports that Ag_3PO_4 is used as gas sensing material for gas detection. Two kinds of Ag_3PO_4 nanomaterials with different morphologies were prepared by ion exchange method and solid phase grinding method. The effect of morphology on the gas sensing properties of NH_3 at room temperature was studied. The results of gas sensitivity test showed that compared with Ag_3PO_4 nanoparticles, the gas sensing properties of the nanotubes were higher than those of Ag_3PO_4 nanoparticles. The sensitivity and selectivity of NH_3 were higher at room temperature, and the detection limit could be as low as 1 Oppm. This work laid a foundation for studying the mechanism of Ag_3PO_4 gas sensing at room temperature and the effect of morphology on its gas sensing reaction activity.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TP212

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