基于纳米材料和光子晶体光纤的分布式气体检测关键技术研究

It is of great significance for protecting environment and personal safety to timely and fastly monitor gas concentration at some dangerous places, especially those are prone to gas poisoning or explosion, such as coal mine, sewer and pipelines with length on the order of tens of kilometers. This project develops a multi-point gas detection system by combining the methods used for processing Rayleigh scattering signal and special hollow core photonic crystal fibers (HC-PCF) whose cores are coated with nano-film (e.g., graphene,cryptophane molecules) which can react to the external gas quickly. This work studies the interaction mechanism between nanomaterials and optical field of HC-PCF, models the near field sensing theory of nanomaterials-PCF based hybrid waveguide. Then effect of HC-PCF and its surface microstructure on increasing evanescent field and sensing is further analyzed in detail.This program also explores methods for fabricating nano-film on the inner wall of hollow core of HC-PCF by optic flow controlling technology. And the response of such a hybrid sensing structure to target gas induced micro concentration modulation is finally studied by experiments. Such a project may provide an alternative way for distributedly detecting gas concentration at multi-points simultaneously and sensitively.

在煤矿、石油化工、下水道等易发生气体中毒或爆炸的领域，由于管道或者矿井的长度达数十上百公里，实时、快速地监测任一位置处的气体浓度对保护环境和保障人身安全具有重要意义。项目提出采用光流控技术在特种空芯光子晶体光纤的纤芯内壁形成快速响应气体的纳米薄膜（如石墨烯、笼形分子化合物），并结合对瑞利散射光信号的处理方法，针对分布式多点气体传感关键技术进行探索研究。具体研究纳米材料与光子晶体光纤光场相互作用机理，建立基于纳米材料-特种光子晶体光纤混合结构的近场光传感理论模型，深入分析光子晶体光纤及其表面微孔结构参数对倏逝场增强效率以及传感增敏效果的影响；探索利用光流控技术在特种光子晶体光纤纤芯空气孔内壁形成纳米分子薄膜新方法；实验研究该混合结构对待测气体痕量物质导致微小浓度调制的传感响应能力。通过本项目的研究希望能为解决准分布式多点气体浓度高灵敏度探测提供一条技术方法。

在碳化硅衬底上外延生长石墨烯是实现石墨烯在微电子领域中应用的最有效途径之一。利用感应加热的高温CVD设备,先在4H-Si C衬底上外延生长一层2~10μm厚的碳化硅,然后直接再在外延碳化硅上原位外延生长石墨烯。实现外延碳化硅-石墨烯的连续生长,从而减少氢气刻蚀带来的晶格缺陷和表面硅富集严重削减现象,并使低成本制备碳化硅上的石墨烯成为可能，并分析探讨了石墨烯气体解吸附特性与解吸附方法。通过实验分析石墨烯对NO2 气体分子的响应时间、气体分子解吸附时间，分析探讨石墨烯的气敏特性。实验表明，石墨烯对NO2 气体传感灵敏度高，响应快，但恢复过程缓慢，气体解吸附时间长，验证了石墨烯对气体具有较好的吸附作用。