Thesis Advisor王钰
Degree Grantor中国科学院研究生院
Degree Name硕士
Degree Discipline材料工程
Keyword气体传感器, 二维材料, 硅纳米线阵列, 异质结构

气体传感器作为建立环境监测系统的“三大基石”之一,越来越为国家所重视。性能优良的气体传感器通常需要具有导电性好、比表面积大、结构有序的特点。随着纳米技术的飞速发展,许多具有这样特性的纳米材料引起了气体传感领域研究者极大的兴趣。例如,具有高载流子迁移率、高比表面积的石墨烯二维材料、硅纳米线阵列等。但是,传统的石墨烯气体传感器恢复时间较长,有的甚至长达数小时;裸硅纳米线极其不稳定,容易被空气氧化,尤其在腐蚀性气氛中,检测环境对于裸硅纳米线的破坏是致命的。 针对以上问题,本研究创新性地提出了一种双管齐下的方法:一方面控制材料形态与尺寸,将普通石墨烯材料制备为石墨烯量子点;另一方面将石墨烯量子点与硅纳米线阵列组装为异质结构。另外,为了简化器件制备,又在石墨烯量子点/硅纳米线阵列的基础上引入了 PEDOT:PSS。本研究主要研究结果如下: 第一, 以硅纳米线阵列为骨架, 采用真空辅助的方法在其外部修饰石墨烯量子点, 组装成石墨烯量子点/硅纳米线阵列异质结构。 较于裸硅纳米线阵列传感器, 石墨烯量子点/硅纳米线阵列传感器对于低浓度 NO2(10ppm)响应的灵敏度提升了将近 10 倍。 同时, 本论文从界面角度研究了传感性能提升的原因,给出了机理解释。 另外,在石墨烯量子点层的保护下, 硅纳米线阵列避免了被氧化,这对于延长器件的使用寿命具有重大意义。 第二, 针对器件制备过程耗时且步骤繁琐的问题, 我们在石墨烯量子点/硅纳米线阵列异质结构基础上进行了改进。 将导电聚合物 PEDOT:PSS 引入到传感体系中, 组装成石墨烯量子点/PEDOT:PSS/硅纳米线阵列结构。 在维持器件传感性能的同时, 将制备时间缩短为原来的 1/3 左右, 同时分析了 PEDOT:PSS 提升石墨烯量子点/硅纳米线阵列传感性能的原因。;As one of the “three cornerstones” for establishing an environmental monitoring system, gas sensors have become more and more important to the country. Gas sensors with excellent performance generally need to have good conductivities, huge specific surface areas, and orderly structures. With the rapid development of nanotechnology, many nanomaterials with such characteristics have attracted great interest from researchers in the field of gas sensing, such as graphene two-dimensional materials and silicon nanowire arrays, which have high carrier mobility and huge specific surface areas. However, the recovery time of traditional graphene gas sensors are very long, and some even up to several hours. The bare silicon nanowire arrays are extremely unstable and easily oxidized by air. Especially in corrosive atmosphere, the detection environment is fatal to the destruction of bare silicon nanowire arrays. In view of the above problems, we proposed a two-pronged approach in this thesis. On the one hand, the graphene materials were prepared into graphene quantum dots by controlling the shape and size of the materials; on the other hand, the graphene quantum dots and silicon nanowire arrays were assembled into a heterostructure. In addition, PEDOT:PSS was introduced in order to simplify thedevice preparation on the basis of graphene quantum dots/silicon nanowire arrays. The main research results of this study are as follows: Firstly, silicon nanowire arrays were used as skeletons and the graphene quantum dots were modified externally by vacuum-assisted method to assemble graphene quantum dots/silicon nanowire arrays heterostructures. Compared to the bare silicon nanowire arrays sensor, graphene quantum dots/silicon nanowire arrays sensor has nearly 10 times higher sensitivity to low-concentration NO2 (10ppm) response. Besides, the reasons for the improvement of the sensor performance from the interface point of view were studied and the mechanism explanation was given in this thesis. In addition, under the protection of the graphene quantum dots layer, the silicon nanowire arrays were prevented from being oxidized, which is of great significance for extending the service life of the devices. Secondly, in order to solve the problem that the fabrication process is time-consuming and cumbersome, we improve the structure of graphene quantum dots/silicon nanowire arrays heterostructures. The conductive polymer PEDOT:PSS was introduced into the sensing system to assemble graphene quantum dots/PEDOT:PSS/silicon nanowire arrays. While maintaining device sensing performance, the preparation time was reduced by nearly 2/3. Meanwhile, the reason for PEDOT:PSS improving the sensing performance of graphene quantum dots/silicon nanowire arrayswas analyzed.Key Words: Gas sensors, two-dimensional materials, silicon nanowire arrays, heterostructures 

Document Type学位论文
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GB/T 7714
李天艳. 二维材料的异质结构组装及其传感机理研究[D]. 中国科学院研究生院,2018.
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二维材料的异质结构组装及其传感机理研究.(2847KB)学位论文 限制开放CC BY-NC-SAApplication Full Text
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