基于表面态调控的W18O49纳米线基室温气体传感器及其自组装研究

NO2 is a typical kind of atmospheric pollutant that would bring serious environmental issues and cause great harm to human health. Therefore it will be an actual demand to research and develop NO2 sensors with high performance and low power consumption. Considering the trend and actuality of research on gas sensor and aiming at the detection of NO2 gas with high sensitivity at room temperature, a study on a new type of room-temperature NO2 gas sensor, which has simple structure, solid performance and is easy to integrate, based on W18O49 nanowire with surface states modulation will be performed. The nanowires-based gas sensor with novel structure and high reliability will be realized through the growth in situ of quai-oriented W18O49 nanowires on the patterned electrode surface and the synchrotron self-assembly of the electrical contacts to nanowires. The developed technology to fabricate nanowires-based sensor can overcome the drawbacks from currently available secondary assembly craft. Furthermore, high sensitivity at room temperature for the W18O49 nanowires-based sensor can be achieved due to the formation of the inversion layer induced by the surface states modulation. During the execution of the project, the effective modulation technique for the surface states and the self-assembly technique for the device, as well as the gas-sensing and nano-effect mechanism will be explored and investigated, and the interdisciplinary research will provide the opportunity to realize 1D nanostructure-based integrated gas sensor with high performance and low power consumption.

NO2是一种对环境和人类健康存在巨大威胁的典型大气污染物，低功耗高性能NO2气体传感器的研究与开发具有重要的实际需求意义。本项目针对新一代气敏传感器的性能特征和研究现状，围绕能够实现NO2气体高灵敏度室温探测的高性能低功耗微传感器探索这一主要目标，提出一种结构简单、性能稳定、易于集成的基于表面态调控的W18O49纳米线基新型NO2室温气体传感器研究。以电极表面W18O49纳米线的图形化准定向原位生长和电极之间纳米线电接触的同步自组装，形成一种结构新颖、性能可靠的纳米线传感元件，克服二次组装工艺的技术缺陷，进一步基于半导体表面态理论，通过结构和表面改性调控纳米线表面态实现纳米线的室温表面反型而获得高的室温气敏灵敏度。本项目通过对表面态有效调控技术和器件自组装工艺以及气敏与纳米效应机制的积极探索，以多学科交叉性研究推进易于集成的、基于一维纳米结构的新一代高性能低功耗气体传感器目标的实现。

提出了表面态调控的W18O49纳米线室温气体传感器及其自组装的研究课题，首先发展了一种W膜热氧化复合后退火工艺实现了在不同传感器基底表面准定向W18O49纳米线阵列的大面积均匀生长；基于W18O49纳米线阵列的可控原位热氧化生长，进一步发展了一种以多晶异质shell层应力诱导法制备均匀W18O49纳米线基核壳有序阵列的创新普适工艺。通过异质纳米线的原位生长和电学接触的自组装实现了基于W18O49纳米线基核壳异质纳米线阵列的传感器的结构自组装，并同时实现了以异质复合多晶shell对W18O49纳米线表面态和气敏性能的有效调控。通过改变多晶shell层，成功制备出了高度定向且壳层均匀的n-W18O49/p-CuO和n-W18O49/n-TiO2、n-W18O49/n-V2O5核壳异质纳米线阵列气体传感器，以多晶shell的高密度表面态、异质界面的界面态和异质结效应的协同调控，实现了W18O49基异质纳米线气体传感器对浓度低至ppb的NO2气体的高室温灵敏度和快速室温响应恢复特性；研究了多晶shell层异质复合、晶格/表面掺杂改性、多级纳米结构构筑三种表面态调控工艺对气体敏感性能的调控特征并建立了物理模型探讨了其表面态调控机制；开展了W18O49纳米线NO2气体吸附体系的DFT计算研究，阐述了W18O49纳米线气敏响应的微观理论机理，给出了纳米线化学计量比和生长方向对气敏响应水平响应能力影响规律的理论预测，并探讨了晶格掺杂、表面氧空位对W18O49纳米线气敏性能的表面态调控的理论机理。项目研究有效解决了微传感器制造中一维纳米线敏感材料在传感器基片表面的集成问题，实现了一维纳米线传感器的结构自组装；通过探索有效的表面态和气敏性能的调控技术，结合DFT计算对敏感性能和敏感机理的理论研究，实现了室温下对NO2气体高度敏感和快速响应的高性能低功耗气体传感器。项目研究实现了预期研究目标，研究内容涉及多学科多前沿技术的交叉，具有重要的学术意义；项目研究成果为进一步推进易于集成的低功耗高性能新型NO2气体传感器的研究与开发奠定了很好的实验与理论基础。