ABSTRACT
Nanocomposites constitute an upcoming class of materials that has enormous potential within a broad range of areas, particularly with regard to mechanical applications. However, the tuning of material properties requires a full understanding of the mechanical response of the nanocomposite across all length scales. While characterization from the micro to macroscale is well established at this point, quantification of mechanical behavior at the nanoscale is still an unresolved challenge. With this background, the current work demonstrates the capabilities of quantitative contact resonance atomic force microscopy (CR-AFM) to localize and reliably characterize Ni nanoparticles that are embedded below the surface of thermally oxidized silicon thin films. Correlating these results with numerical simulations as well as high-resolution transmission electron microscopy measurements provides a comprehensive understanding of the subtle interplay between the structure and nanomechanical response of the composite.
ABSTRACT
Contact resonance atomic force microscopy (CR-AFM) constitutes a powerful approach for nanometer-resolved mechanical characterization of surfaces. Yet, absolute accuracy is frequently impaired by ad hoc assumptions on the dynamic AFM cantilever characteristics as well as contact model. Within the present study, we clarify the detailed interplay of stress fields and geometries for full quantitative understanding, employing combined experimental numerical studies for real AFM probes. Concerning contact description, a two-parameter ansatz is utilized that takes tip geometries and their corresponding indentation moduli into account. Parameter sets obtained upon experimental data fitting for different tip blunting states, are discussed in terms of model-specific artificiality versus real contact physics at the nanoscale. Unveiling the underlying physics in detail, these findings pave the way for accurate characterization of nanomechanical properties with highest resolution.
