嵌入压阻硅纳米线的高灵敏VOC气体传感器的研究

Due to the volatile organic compounds have highly toxic and strong carcinogenesis to human, development of vapor sensor with miniaturization 、easy integration、low cost and high sensitivity has important significance to protect the human health and environment. In this work, the transducer of vapor sensor based on giant piezoresistive effect of the silicon nanowire and low Young's modulus of the parylene material is fabricated by Micro-electro-mechanical processing technology to detect the swelling stress of the vapor sensitive films. This project study of the giant piezoresistive effect formation mechanism of the silicon nanowire and the effect of correlative parameters on the piezoresistive properties and electrical properties of silicon nanowire, which will be benefit for fabricating piezoresistive silicon nanowire. A model of the vapor sensor is presented based on gas adsotption-diffusion theory and elastic plate theory to discuss the coupling mechanism between vapor sensing material and the transducer and optimize the parameters of the vapor sensitive films. Finally，the vapor sensing material are modified with a functionalized gold nanoparticles film to improve the selectivity of the sensor. This project will provide the theory and technology foundation for developing high performance VOC vapor sensor.

挥发性有机物(Volatile organic compounds，VOC)具有很强的毒性和致癌性，研制微型化、易集成、低成本、高灵敏度的气体传感器对保护人体健康和环境具有重要的意义。本项目利用p型硅纳米线的巨压阻效应，采用自上而下的MEMS工艺，将p型硅纳米线作为压敏元件嵌入杨氏模量较低的Parylene膜中制备高性能的力敏换能器，并结合功能化高分子气敏薄膜，研制出高灵敏压阻式VOC气体传感器。本项目深入研究硅纳米线巨压阻效应的形成机理，明晰硅纳米线的各项参数对其压阻特性及电学特性的影响规律，为稳健设计制备压阻硅纳米线提供指导依据；结合气体吸附、扩散理论和弹性薄板理论构建传感器的模型，研究气敏膜吸附气体溶胀形变与力敏薄膜相互耦合机理，优化传感器气敏膜的参数设计；合成功能化金纳米颗粒修饰气敏薄膜，改善传感器的选择性。本项目的研究结果将为研制高性能压阻式VOC气体传感器奠定理论和技术基础。

挥发性有机物(volatile organic compounds，VOC)具有很强的毒性和致癌性，研制微型化、易集成、低成本、高灵敏度的气体传感器对保护人体健康和环境具有重要的意义。原计划利用p型硅纳米线的巨压阻效应，研制出高灵敏压阻式VOC气体传感器。在项目实施中，我们研究了硅纳米线的各项参数对其压阻特性及电学特性的影响，得到了优化后的硅纳米线的设计参数。同时结合气体吸附、扩散理论和弹性薄板理论构建了传感器的模型，基于该模型确定了气敏膜和支撑薄膜结构的参数。然而，受制于硅纳米线的超精密加工工艺条件和项目经费，我们又提出了采用体声波谐振器（Film bulk acoustic resonator，FBAR）作为力敏检测单元代替硅纳米线制备高灵敏的VOC气体传感器的方案，在上述传感器模型的基础上，结合第一性原理和FBAR 的 mason模型，构建了基于FBAR的传感器模型，得到了传感器的理论输出，为优化传感器的设计提供准则。结合试制的结果，优化后的氯仿气体传感器的检测灵敏度约为200ppb/HZ。该项目的研究结果将为研制高性能谐振式VOC气体传感器奠定理论和技术基础。