二氧化碲—维纳米结构的气敏性能研究

发布时间：2018-01-05 22:13

本文关键词：二氧化碲—维纳米结构的气敏性能研究　出处：《湖南师范大学》2015年硕士论文　论文类型：学位论文

【摘要】：TeO2作为宽禁带的P型半导体材料,对氧化还原性气体具有极高的灵敏度,在气敏传感方面展现了优越的性能。本文在室温下对TeO2准一维纳米结构的气敏性能进行了深入的研究。以纯净的Te粉为原料,以揗有2纳米金膜的硅片作为衬底,采用化学气相沉积法制备出TeO2准一维纳米结构。采用XRD,SEM表征TeO2准一维纳米结构的相组成以及微观结构。结果表明,TeO2纳米线具有四方相晶体结构,长度约为几十微米,直径约为50~200nm之间。在TeO2纳米线的顶端未发现Au颗粒,表明TeO2纳米线按照气-固机制进行生长。利用金属丝掩膜法,构筑了基于单根TeO2准一维纳米结构的“金属/TeO2准一维纳米结构/金属”电阻型气敏传感器件。室温下测试了传感器件在不同环境(空气、真空、H2S)下的电输运性能,探讨了气体吸附对器件电导率的影响。在大气中,由于氧分子的吸附,增加了空穴浓度,器件的电导增强,而在强还原性硫化氢气体中,器件电导减少。同时发现器件具有忆阻效应,空气中氧空位浓度的增加增强了忆阻效应,硫化氢中多数载流子空穴的减少抑制了忆阻效应,证实了忆阻机理:氧空位在电场的作用下发生迁移,改变了接触势垒宽度,增强电子隧穿几率,从而改变电导,导致忆阻现象。研究表明,在室温下二氧化碲准一维纳米结构对氧化还原性气体具有极高的灵敏度。为实现低功耗,室温工作的高性能气敏传感器提供了气敏元件基础。
[Abstract]:As a P-type semiconductor material with wide bandgap, TeO2 has a high sensitivity to redox gases. In this paper, the gas-sensing properties of TeO2 quasi-one-dimensional nanostructures were studied at room temperature. Pure Te powder was used as raw material. TeO2 quasi one-dimensional nanostructures were prepared by chemical vapor deposition on silicon wafers with 2 nanocrystalline gold films. XRD was used as the substrate. The phase composition and microstructure of TeO2 quasi one-dimensional nanostructures were characterized by SEM. The results show that TeO2 nanowires have tetragonal crystal structure and the length is about tens of microns. Au particles were not found at the top of TeO2 nanowires, indicating that TeO2 nanowires were grown according to gas-solid mechanism. A resistive gas sensing device of "metal / TeO2 quasi one-dimensional nanostructure / metal" based on a single TeO2 quasi-one-dimensional nanostructure is constructed. The sensing devices in different environments (air, vacuum) are tested at room temperature. The influence of gas adsorption on the conductivity of the device is discussed. In the atmosphere, the density of hole increases and the conductance of the device increases due to the adsorption of oxygen molecules. However, in the strongly reductive hydrogen sulfide gas, the device conductance is reduced. At the same time, it is found that the device has the effect of amnesia, and the increase of oxygen vacancy concentration in the air enhances the effect of the device. The reduction of most carrier holes in hydrogen sulfide inhibits the amnesia effect, which confirms the mechanism of amnesia: oxygen vacancies migrate under the action of electric field, the width of contact barrier is changed, and the probability of electron tunneling is enhanced. It is shown that the quasi-one-dimensional tellurium oxide nanostructures have high sensitivity to redox gases at room temperature. The high performance gas sensor operating at room temperature provides the basis of the gas sensor.
【学位授予单位】：湖南师范大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ125.3;TB383.1

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