Photo Thermal Induced Resonance (PTIR), recently attracted great interest for enabling chemical identification and imaging with nanoscale resolution. In this paper, the PTIR working principles are reviewed along the main results from a recent publication aimed to assess the PTIR lateral resolution, sensitivity and linearity. For this purpose nano-patterned polymer samples were fabricated using electron beam lithography directly on 3-dimentional zinc selenide prisms. Results show that the PTIR lateral resolution for chemical imaging is comparable to the lateral resolution obtained in the AFM height images, up to the smallest feature measured (100 nm). Spectra and chemical maps were produced from the thinnest sample analyzed (40 nm). Notably, our experiments show that the PTIR signal increases linearly with thickness for samples up to ≈ 1 µm (linearity limit); a necessary requirement towards the use of the PTIR technique for quantitative chemical analysis at the nanoscale. Finally, the analysis of thicker samples provides evidence that the previously developed PTIR signal generation theory is correct. We believe that our findings will foster nanotechnology development in disparate applications by proving the basis for quantitative chemical analysis with nanoscale resolution.
Citation: Microscopy and Analysis
Pub Type: Journals
Infrared Spectroscopy, Chemical Imaging, Nanoscale Characterization, AFM, Electron Beam Lithography.