纳米多孔硅材料表面对气体吸附的特异性使其在瓦斯气体传感器领域有广泛的应用。本文以多孔硅表面瓦斯气体吸附过程为研究对象，利用理论与实验结合的方法研究瓦斯气体与多孔硅材料表面相互作用过程，以期得到器件表面的物理和化学吸附规律，这将对于纳米硅材料传感器有很重要的研究意义。 气敏元件设计中要考虑不同硅表面与气体吸附浓度的依赖关系和同一表面的不同吸附位置与吸附稳定性的关系。本文主要从硅吸附质表面形貌、表面对瓦斯气体的物理和化学吸附过程进行了相关分析。利用气相色谱仪和物理化学吸附仪，分析了不同数量Si(311)表面对瓦斯气的物理吸附的影响；恒温下不同浓度的甲烷气体吸附过程及不同温度时甲烷气体的化学吸附。理论方面，采用以密度泛函理论为基础的material studio软件分析CH4、CO分子在不同硅表面、不同吸附位置的物理和化学吸附。 物理吸附的实验数据表明由于多孔硅表面介孔分布较多，甲烷气在多孔硅表面的物理吸附是较弱的稳定吸附。随着硅片数量的增加，可以改善单独硅表面对甲烷气体弱吸附作用。化学吸附的实验展示的规律是60-80℃时甲烷气不能与Si(311)表面发生化学吸附，在100℃时甲烷发生稳定的化学吸附。理论模拟的结果显示，甲烷在硅表面呈现各面异性，吸附位置、覆盖率、距离对表面的影响较大，吸附角度对表面的影响小。CH4、CO同时物理吸附在表面，Si(311)对甲烷的敏感性更强。化学吸附结果表明Si-C较强的键合作用使得甲烷分子离解为甲基和H原子，分别与硅表面原子形成新的化学键，电子云重构和由于电子转移导致态密度分子轨道电子峰的离域性变大，出现新的能带群，展示了相应化学键形成的动态过程。 多孔硅的介孔结构分布较多，孔隙率较大，对瓦斯气体的气敏性较强，可以作为探测瓦斯气体的衬底材料。课题所得结论为多孔硅气敏元件的研发提供实验和理论指导。

The porous silicon surface is widely used in the sensor field, which is due ro the adsorption specifity of gas on the nanometer porous silion surface. Using the theoretical and experimental methods, the adsorbing process of gas on the porous silicon surface is analyzed. The physical and chemical kinetic process of the CH4, CO on device surface is obtained, which plays an important role on the devise of nano-silicon sensors. For designing the gas sensors, we need to consider the different adsorbing capacity depends on the different Si surface and the adsorption sites are related to the stability of gas on surface. We mainly investigate the silicon surface appearance and the physical adsorption and chemical adsorption process of the gas on Si surface. Using the gas chromatography and Autosorb-iQ-C, we analyze the gas physical adsorption on the different number Si (311) surface, the methane adsorbing capacity changes with the different pressures when the temperature is constant and the methane chemical adsorbing on the Si (311) surface in the different temperatures. Additionally, the material studio software which is based on the DFT is used to analyze the physical and chemical adsorption of CH4 and CO molecules on different Si surface and different adsorption sites in theoretical sides. The physical adsorption experiment results show that the porous silicon surface distribute so many mesoporous that the weak physical adsorption of CH4 on Si surface. However, the gas physical adsorbing capacity increased with the the silicon number change. The increased Si number improves the weak physical adsorption of methane on Si surface. Then the chemical adsorption data illustrate the Si (311) surface can not interact with methane at 60-80℃, and the chemical adsorption effect of CH4 and Si surface occur at 100℃. The adsorption models theoretically show anisotropy of CH4 adsorbing on Si surface, and adsorption sites, coverage and distance have large impact on Si surface, but the effects of adsorded molecule direction are small. When CH4 and CO physical adsorbed on the Si (311) surface, Si surface is more sensitive to methane. The chemical adsorption displays Si-C strong bonding effect lead to the methane decompose to methyl and H atom, which bonds with silicon surface atoms, respectively. The electron cloud reconstructs, and with the electron transfer, the PDOS molecular orbit electron peaks delocalization are strong and appear new band group, which show the chemical bonds formed. The gas absorbing sensitivity of porous silicon surface is strong, because the mesoporous structure and the large porosity. So the Si (311) surface can be used as the substrate to detect gas. The conclusion can provide the experimental and theoretical instruction for porous silicon gas sensor design.