By Dr. Cameron Chai
Scientists at nanoGUNE and Neaspec have developed the nano-FTIR, an infrared spectrometer that enables infrared spectra recording with a thermal source at 100 times better resolution than traditional infrared spectroscopy.
The method could be used for evaluating the arrangement of nanomaterials and local chemical constitution in various semiconductor instruments, polymer composites biological tissue and minerals. The research work is available in Nature Materials journal.
Infrared ray absorption is distinctive for material structure and chemical composition. Hence, infrared spectrum has been considered as a significant tool for differentiating and recognizing materials. It is extensively applied in biomedical investigations and materials sciences. With traditional optical devices like Fourier Transform Infrared spectrometers, focusing the light at a particular spot sizes less than few micrometers is not possible. This basic restriction avoids infrared-spectroscopic mapping of individual molecules, nanoparticles or new semiconductor devices.
The nano-FTIR is developed on the basis of a scattering-type near-field microscope (NeaSNOM). The topography of the specimen’s surface is scanned using the pointed metallic point of the NeaSNOM and during scanning the tip is lighted up using infrared light. The tip serves as an antenna and transforms the incident radiation into an infrared spot of nanoscale at the top of the tip. By assessing the dispersed infrared radiation with an exclusively developed FTIR spectrometer, infrared spectra from undersized specimen volumes can be recorded.
During the investigations, the scientists captured an infrared picture of a semiconductor device developed by Infineon Technologies. FlorianHuth, who conducted the investigations, stated that they accomplished a spatial resolution surpassing 100 nm, directly depicting that thermal radiation can be concentrated to a point size. In contrast to traditional infrared spectroscopy, the size of the dot will be hundred times smaller.
FlorianHuth explained that the nano-FTIR can be used for identifying silicon oxides that were processed in a different way or for determining the local electron density in complicated industrial electronic instruments. He added that their method enables them to record spectra in the range of near- to far-infrared spectrum, thereby serving as a major aspect for examining the chemical constitution of unidentified nanoscale materials.
In future, the nano-FTIR can be used in several applications, including semiconductors, astrophysics and nanogeochemistry. FlorianHuth mentioned that the nano-FTIR, based on vibrational fingerprint spectroscopy, could be used for nano-level mapping of structural characteristics and chemical composition of inorganic and organic nano-systems such as nanowires, solar cells, organic semiconductors and minerals.