Nano-FTIR Correlation Nanoscopy for Organic and Inorganic Material Analysis
Scattering-type Scanning Near-field Optical Microscopy (s-SNOM) is a scanning probe approach to optical microscopy and spectroscopy bypassing the ubiquitous diffraction limit of light to achieve a spatial resolution below 20 nanometers. s-SNOM employs the strong confinement of light at the apex of a sharp metallic AFM tip to create a nanoscale optical hot-spot. Analyzing the scattered light from the tip enables the extraction of the optical properties (dielectric function) of the sample directly below the tip and yields nanoscale resolved images simultaneous to topography . In addition, the technology has been advanced to enable Fourier-Transform Infrared Spectroscopy on the nanoscale (nano-FTIR)  using broadband radiation from the visible spectral range to THz frequencies. Recently, the combined analysis of complex nanoscale material systems by correlating near-field optical data with information obtained by other SPM-based measurement methodologies has gained significant interest. For example, the material-characteristic nano-FTIR spectra of a phase-separated PS/LDPE polymer blend verifies sharp material interfaces by measuring a lineprofile across a ca. 1μm sized LDPE island (Fig1). Near-field reflection/absorption imaging at 1500cm-1 of the ca. 50nm thin film allows to selectively highlight the distribution of PS in the blend and simultaneously map the mechanical properties like adhesion of the different materials [3,4].
Further, results will be presented that correlate the near-field optical response of semiconducting samples like Graphene (2D) or functional SRAM devices (3D) in different frequency ranges (mid-IR & THz) to Kelvin Probe Force Microscopy (KPFM) measurements. Thus, neaspec s-SNOM systems represent an ideal platform to characterize complex material systems by different near-field and AFM-based methods at the nanoscale.
Fig 1. Near-field correlation nanoscopy of a thin PS/LDPE polymer film, highlighting the phase separation of the materials by nano-FTIR measurements as well as the different mechanical properties of the polymers.
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 I. Amenabar, et al., Nature Commun. 8, 14402 (2017).
About The Speaker
Andreas Huber graduated in Physics from TU Munich, Germany, in 2005. He then joined the group of Prof. Rainer Hillenbrand at the Max-Planck-Institute of Biochemistry for his PhD project to work on infrared near-field microscopy. In 2009 he started to work for neaspec, now as Director Sales & Applications Development. Since the very beginning of his scientific work Andy was focused on near-field microscopy and spectroscopy applications in wide spectral range from visible to infrared wavelengths, with special focus on the THz frequency range