C.A. Phillips, Q. Hu, C. Li, P. De Wolf
Bruker Nano,
United States
Keywords: nanoIR, SPM, AFM, AFM-IR, s-SNOM, nanoscale infrared spectroscopy
Summary:
As material components and devices become smaller and more complex, the need for nanoscale optical characterization and chemical identification grows rapidly. The diffraction limit traditionally restricts the lateral resolution of optical measurements to approximately half of the wavelength of light-on the order of microns in the mid infrared region-making it challenging to achieve high-resolution chemical analysis. This limitation has spurred a long-standing need for robust techniques that can overcome these constraints and provide detailed nanoscale chemical information. Nanoscale infrared (nanoIR) spectroscopy has significantly enhanced our ability to study the chemical properties of materials at the molecular level, and a number of techniques have been developed to conquer the diffraction limit. Three of the main SPM coupled nanoscale IR techniques are photothermal AFM-IR, photoinduced force microscopy (PiFM) and scattering-type scanning near-field optical microscopy (s-SNOM). However, significant ambiguities remain regarding their detection mechanisms and which technique is optimal for a specific application, leaving room for continuous efforts and further discovery. This presentation aims to provide a comprehensive introduction to these three prominent techniques. We will discuss the unique advantages each method offers, and their contrast mechanisms, as well as the respective limitations, including sample preparation and the complexity of data interpretation. A key objective is to resolve common ambiguities in the terminology associated with these techniques, fostering a clearer understanding and providing a common language for researchers in the field. Applications beyond the infrared range will also be explored. By addressing these nuances, we aim to enable a more precise comparison of the methods and encourage their effective application across a wide range of scientific disciplines. This talk will offer attendees a solid foundation to better navigate the diverse nanoIR landscape, facilitating informed decisions about which technique best suits their research needs.