【作者】 潘进；

【导师】 黎学明；

【作者基本信息】 重庆大学 ， 应用化学， 2003， 硕士

【摘要】 二氧化硫(SO2)的大量排放对环境造成了严重污染，采用有效手段动态监测SO2的含量则是控制SO2排放的根本保证。由于现行SO2监测方法存在诸多问题，迫切需要价格低廉、灵敏度高、选择性好、抗电磁干扰能力强、可实时在线监测SO2的新型传感技术。多孔硅是一种具有以纳米硅原子簇为骨架构成的海绵状结构、比表面积高和生物相容性好的新型功能材料，正日益受到人们重视。本文以不同掺杂类型的单晶硅片作为研究对象，采用电化学阳极氧化法制备多孔硅并对其进行稳定化处理，利用多种仪器对多孔硅的理化性质、结构、SO2传感性能等进行实验研究。主要的工作和结论如下： 1) 研究了不同掺杂类型、电化学阳极氧化条件和稳定化处理方法等对多孔硅性能的影响；采用荧光光谱仪、扫描电子显微镜（SEM）、原子力显微镜（AFM）、红外光谱（FT-IR）等仪器表征多孔硅的膜厚、孔隙率、表面形态、结构、光致发光、耐蚀性等性质；获取了多孔硅最佳制备工艺条件和稳定化处理条件。 2) 开展了多孔硅对SO2传感的定性、定量研究，证明新鲜浸蚀的多孔硅和稳定化处理的多孔硅均对SO2气体表现出良好的光激荧光猝灭特性，多孔硅荧光峰猝灭幅度与SO2浓度之间呈正相关；根据SEM、耐碱性实验和SO2传感实验结果可知，n-Si制备的多孔硅经稳定化处理后膜层完整、不炸裂、稳定性好、传感SO2气体灵敏度高，比p-Si更适宜作为环境中SO2气体的传感材料。3) 计算了不同实验条件下的Stern-Volmer 常数KS数值的大小。当SO2浓度在0-0.25mL·L-1范围时，多孔硅传感过程服从Stern-Volmer方程。其中：经紫外（UV）光氧化处理的多孔硅的Stern-Volmer常数为0.5；经氢化硅烷化处理的多孔硅的Stern-Volmer常数为0.7。当SO2浓度较高时，多孔硅传感SO2的过程不符合Stern-Volmer线性方程。4) 环境中的NOx、COx、N2等基本不干扰二氧化硫测定，即多孔硅对SO2呈现良好的选择性。更多还原

【Abstract】 Sulphur dioxide (SO2) is a main contaminant in air and also the pollutant primarily associated with acid rain. The principal sources of SO2 are from the combustion of fossil fuel in domestic premises, and more importantly, non-nuclear power station. In many countries, the economical losses resulting from sulphur dioxide and acid rain are very great, which makes monitoring SO2 in environment is a critical part in pollution prevention, industrial and agricultural contamination regulations. At present, several methods and instruments are available to monitor SO2 concentration both in gaseous and in liquid media using different systems including colorimetric, amperometric, conductometric, gas chromatography, flame photometry, surface acoustic wave (SAW) gas sensor, tin dioxide gas sensor as well as electrochemical sensors based on high temperature solid electrolyte, liquid electrolyte, solid polymer electrolyte, etc. But these techniques have their own characteristics and limits, new approaches to the detection and analysis of SO2 appear to be in dire need. As a novel functional material, porous silicon is constituted by a nano-crystalline skeleton (quantum sponge) immersed in a network of pore, and has a very large internal surface area and good bio-compatibility. So far, chemical properties, physical properties and optical properties of the material have been studied extensively. Because porous silicon can be easily synthesized directly from the same single-crystal silicon wafers, it seems ideal for Si-based opto-electronic devices, bio- and chemical sensors, mass spectrometry, new material support, biocompatible materials and in vivo electronics etc. In this dissertation, porous silicon is formed by electrochemical anodization of p- or n-type single-crystal silicon materials. In order to hinder oxidization process of porous silicon in air, either hydrosilylation or photochemical oxidization is used to stabilize porous silicon, whose principle is based on silicon hydride bonds of porous silicon are replaced by silicon alkyls or silicon dioxide. Furthermore, its structure, properties and sensing process are studied experimentally. The main points of this dissertation are as following: 1) The effect of dopant of single-crystal silicon, anodization parameters, stabilization methods on porous silicon formation is studied extensively. By fluorescent spectrometer, SEM, AFM, FT-IR, etc., the properties of porous silicon such as porosity, thickness, structure, morphology, photoluminescence, anti-corrosion ability, are measured, the<WP=6>corresponding optimal conditions of fabrication and stabilization for porous silicon are obtained. Analyzed these experimental results, it is proved that porous silicon generating from n-type silicon wafer is more stable than that of p-type silicon. 2) According to the experimental results of porous silicon sensing SO2 qualitatively and quantitatively, it is discovered that photoluminescence quenching values of porous silicon oxidized by n- or p-type single-crystal silicon wafers is positively correlated with concentration of SO2. Moreover, stabilization method based on white-promoted hydrosilylation is superior to photochemical oxidization.3) The corresponding Stern-Volmer constant KS is also calculated according to the experimental results of photoluminescent quenching process. Within the concentration range from 0 to 0.25mL·L-1, the quenching process is in accord with Stern-Volmer equation. The Stern-Volmer conatant KS of UV oxidation porous silicon is equal to 0.5,and that of hydrosilylation porous silicon is 0.7. Within high concentration range, the quenching process isn’t in accord with Stern-Volmer equation.4) The other gas such as N2, COx, NOx in monitoring environment cann’t disturb the sensing process of SO2.更多还原