The interlayer bonding in two-dimensional (2D) materials is particularly important because it is not only related to their physical and chemical stability but also affects their mechanical, thermal, electronic, optical, and other properties. To address this issue, we report the direct characterization of the interlayer bonding in 2D SnSe using contact-resonance atomic force microscopy (CR-AFM) in this study. Site-specific CR spectroscopy and CR force spectroscopy measurements are performed on both SnSe and its supporting SiO₂/Si substrate comparatively. Based on the cantilever and contact mechanic models, the contact stiffness and vertical Young’s modulus are evaluated in comparison with SiO₂/Si as a reference material. The interlayer bonding of SnSe is further analyzed in combination with the semi-analytical model and density functional theory calculations. The direct characterization of interlayer interactions using this non-destructive methodology of CR-AFM would facilitate a better understanding of the physical and chemical properties of 2D layered materials, specifically for interlayer intercalation and vertical heterostructures.

二维（2D）材料中的层间粘合特别重要，因为它不仅与它们的物理和化学稳定性有关，而且还影响它们的机械，热，电子，光学和其他特性。为了解决这个问题，我们在这项研究中报告了使用接触共振原子力显微镜（CR-AFM）对2D SnSe中的层间键合进行直接表征的过程。分别在SnSe及其支撑SiO ₂ / Si基板上进行了特定位置的CR光谱和CR力光谱测量。基于悬臂和接触力学模型，与SiO ₂相比，评估了接触刚度和垂直杨氏模量/ Si作为参考材料。结合半分析模型和密度泛函理论计算，进一步分析了SnSe的层间键合。使用CR-AFM的这种非破坏性方法来直接表征层间相互作用将有助于更好地理解2D层状材料的物理和化学性质，特别是对于层间插层和垂直异质结构。