Versatile automated AFM-Raman, SNOM and TERS system
NTEGRA Spectra II is the first system on the market that seamlessly integrates the best of two worlds: AFM and Raman microscopy.
From topography to spectrum analysis, from electrical and mechanical properties to optical spatial resolution below the diffraction limit.
At the fingertips of scientists now is the capability to run a full surface analysis of a sample along with chemical study of the same area of interest.
Researches now receive unlimited possibilities to extend their laboratory capacity.
Tip Enhanced Raman Scattering allows carrying out spectroscopy/microscopy with nanometer scale resolution.
TERS imaging requires prolonged tip-sample contact at each scanning point, but Contact AFM is destructive for both the tip and the sample.
Thereby, HybriD ModeTM is a superior technique for cantilever-type TERS since it dramatically increases the tip lifetime, allows non-destructive studies, and besides enables Quantitative Nanomechanics.
The presented results using the example of graphene oxide flakes, show that HybriD ModeTM allows one to effectively enhance the Raman scattering and, at the same time, significantly reduces the mechanical effect on the sample and on the probe during scanning.
Program has been developed with the help of neural networks to provide auto-tuning of scanning parameters for imaging in AM-AFM.
Automatic maintenance of attractive (non-contact) & repulsive (intermittent-contact) regimes.
Artefact-free scanning without parachuting. Perfect performance at samples with any kind of morphology.
To learn more
- Optical techniques (color imaging, physical & chemical analysis)
- Scanning probe microscopy (topography, mechanical, electrical, magnetic and other properties of the surface)
- AFM (STM) + Optical techniques = Dramatic increase of resolution and sensitivity
* Compatibility with other wavelength upon request
CdS nanowire was connected with metal electrode by conductive polymer nanowires. AFM probe is positioned on the structure with the help of viewing microscope. Thanks to the shape of the AFM probe laser can be positioned directly onto the tip apex.
High resolution AFM images provide information about sample topography. Raman and luminescence maps taken from the same area show difference in nanowires chemical composition.
Fast Raman mapping is a crucial option for high-speed processes detection. Thanks to galvanic scanning mirror technology it is possible to acquire Raman map of selected band with acquisition time down to <50 us/point, which is about 1 sec/image.
Build-in capacitance sensors make possible laser spot positioning with precision less than 20 nm. This is especially important when one need to select a particular point on the acquired Raman map and position spot there for a long time. For example for "hot spot" finding in TERS or aperture finding in SNOM.
NTEGRA Spectra II allows to combine a recently developed innovative HybriD Mode™ (HD-AFM™ Mode) for nanomechanical proprieties and Raman for chemical imaging of exactly the same area within single measurement session.
In HybriD mode the tip-sample distance is modulated according to the quasi-harmonic law. Thus tip enters a force interaction with the sample thousands times per second. Force-distance curve analysis enables maps of topographical, nanomechanical, electrical, thermal and piezoelectric properties of the sample to be extracted with high spatial resolution and minimized lateral forces.
High-performance electronic components and unique algorithms implemented in the state-of-the-art HybriD 2.0 Control Electronics provide superb level of real-time signal processing and analysis. Combining mode with cutting-edge optical microscopy and spectroscopy techniques opens-up novel opportunities of cantilever-based tip-enhanced Raman scattering (TERS) and scattering scanning near-field optical microscopy (s-SNOM).
Principle of Tip Enhanced Raman Scattering and other tip- assisted optical techniques (left). Localized surface plasmon (electron density oscillations) at the end of a metal TERS probe (nano-antenna), resulting in light localization and enhancement at the probe apex (right).
Tip Enhanced Raman Scattering (TERS, nano-Raman) is the technique for enhancement of weak Raman signals and for super-resolution Raman imaging with spatial resolution ~10 nm. Nano-Raman imaging provides unique insights into sample structure and chemical composition on the nanometer scale.
In TERS, a sharp metal probe (nano-antenna) is used to localize and enhance optical field at the tip apex. The light enhancement is typically reached when excitation laser light is in resonance with localized surface plasmon at the end of the TERS probe. Enhancement of electromagnetic field (light) intensity on the TERS probe apex can reach many orders of magnitudes. In TERS mapping the sample is scanned with respect to the nano-antenna; the enhanced Raman signal localized near the probe apex is measured resulting in Raman maps of the sample surface with nanometer scale resolution.
NT-MDT develops and supplies unique instrumentation for AFM integration with various optical microscopy and spectroscopy techniques. NT-MDT was the first to introduce integrated AFM-Raman instrument in 1998 and is now the leading developer and supplier of such instruments worldwide.
NT-MDT AFM-Raman instrument has been successfully used for TERS (nano-Raman) mapping of various objects with spatial resolution reaching 10 nm: graphene and other carbon nanomaterials, polymers, thin molecular layers (including monolayers), semiconductor nanostructures, lipid membranes, various protein structures, DNA molecules etc.
References to corresponding publications can be found at More information.
As a result of comprehensive research performed together with NT-MDT customers and partners, NT-MDT is now able to offer to its AFM-Raman customers mass produced reproducible cantilever-type TERS probes. The probes are prepared based on so-called “Top Visual” AFM Si cantilevers. Special proprietary probe preparation and TERS metal coating are applied.
AFM probes can have different stiffness and can be optimized for contact and non-contact regimes.
Protruding “nose-type” shape of the probes allows Raman laser light to be focused on the probe apex from the top: for use with non-transparent samples.
The probes provide guarantied TERS performance on a test sample (organic molecules on Au substrate):
SEM image of “Top Visual” AFM probe. Protruding probe geometry allows optical access to the apex from the top (left). Experimental TERS configuration (right).
The AFM TERS probes also feature excellent AFM performance in contact and non-contact regimes since they are prepared based on standard Si AFM cantilevers produced by mass technology. All advanced AFM modes (electrical, magnetic, nanomechanical etc.) are available with NT-MDT TERS probes. High resonance quality factors (for non-contact probes) allow excellent force sensitivity and guarantee long tip lifetime during measurements.
STM TERS probes (electrochemically etched metal wires) and TERS probes attached to tuning fork are also available.
The NT-MDT TERS probes reach their highest characteristics with the unique AFM-Raman instrument from NT-MDT: specifically designed for TERS research.
Probes are only supplied to be used with NT-MDT instrumentation. Contact us for more information.
More technical information about TERS cantilevers: http://www.ntmdt-tips.com/products/group/ters-afm-probes-new
