Fourier-transform infrared (FTIR) spectroscopy is a widely used analytical tool for chemical identification of inorganic, organic and biomedical materials, as well as for exploring conduction phenomena. Because of the diffraction limit, however, conventional FTIR cannot be applied for nanoscale imaging. Here we demonstrate a novel FTIR system that allows for infrared-spectroscopic nanoimaging of dielectric properties (nano-FTIR). Based on superfocusing of thermal radiation with an infrared antenna, detection of the scattered light, and strong signal enhancement employing an asymmetric FTIR spectrometer, we improve the spatial resolution of conventional infrared spectroscopy by more than two orders of magnitude. By mapping a semiconductor device, we demonstrate spectroscopic identification of silicon oxides and quantification of the free-carrier concentration in doped Si regions with a spatial resolution better than 100 nm. We envisage nano-FTIR becoming a powerful tool for chemical identification of nanomaterials, as well as for quantitative and contact-free measurement of the local free-carrier concentration and mobility in doped nanostructures.
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http://dx.doi.org/10.1038/nmat3006 | DOI Listing |
Nano Lett
April 2022
State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, People's Republic of China.
Oxide heterointerfaces with high carrier density can interact strongly with the lattice phonons, generating considerable plasmon-phonon coupling and thereby perturbing the fascinating optical and electronic properties, such as two-dimensional electron gas, ferromagnetism, and superconductivity. Here we use infrared-spectroscopic nanoimaging based on scattering-type scanning near-field optical microscopy (s-SNOM) to quantify the interaction of electron-phonon coupling and the spatial distribution of local charge carriers at the SrTiO/TiO interface. We found an increased high-frequency dielectric constant (ε = 7.
View Article and Find Full Text PDFSci Rep
November 2021
Fakultät für Physik, Nano Institute Munich & Center for NanoScience (CeNS), Ludwig-Maximilians-Universität, Königinstr. 10, 80539, Munich, Germany.
Infrared fingerprint spectra can reveal the chemical nature of materials down to 20-nm detail, far below the diffraction limit, when probed by scattering-type scanning near-field optical microscopy (s-SNOM). But this was impossible with living cells or aqueous processes as in corrosion, due to water-related absorption and tip contamination. Here, we demonstrate infrared s-SNOM of water-suspended objects by probing them through a 10-nm thick SiN membrane.
View Article and Find Full Text PDFLight Sci Appl
April 2021
State Key Laboratory of Physical Chemistry of Solid Surfaces, Collaborative Innovation Center of Chemistry for Energy Materials, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, China.
Organic-inorganic halide perovskites are emerging materials for photovoltaic applications with certified power conversion efficiencies (PCEs) over 25%. Generally, the microstructures of the perovskite materials are critical to the performances of PCEs. However, the role of the nanometer-sized grain boundaries (GBs) that universally existing in polycrystalline perovskite films could be benign or detrimental to solar cell performance, still remains controversial.
View Article and Find Full Text PDFNat Commun
June 2014
1] Fakultät für Physik and Center for NanoScience (CeNS), Ludwig-Maximilians-Universität München, Geschwister-Scholl-Platz 1, 80539 München, Germany [2] Nanosystems Initiative Munich, Schellingstrasse 4, 80799 München, Germany.
Controlling the domain size and degree of crystallization in organic films is highly important for electronic applications such as organic photovoltaics, but suitable nanoscale mapping is very difficult. Here we apply infrared-spectroscopic nano-imaging to directly determine the local crystallinity of organic thin films with 20-nm resolution. We find that state-of-the-art pentacene films (grown on SiO2 at elevated temperature) are structurally not homogeneous but exhibit two interpenetrating phases at sub-micrometre scale, documented by a shifted vibrational resonance.
View Article and Find Full Text PDFNat Mater
May 2011
Nanooptics Group, CIC nanoGUNE Consolider, 20018 Donostia-San Sebastián, Spain.
Fourier-transform infrared (FTIR) spectroscopy is a widely used analytical tool for chemical identification of inorganic, organic and biomedical materials, as well as for exploring conduction phenomena. Because of the diffraction limit, however, conventional FTIR cannot be applied for nanoscale imaging. Here we demonstrate a novel FTIR system that allows for infrared-spectroscopic nanoimaging of dielectric properties (nano-FTIR).
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!