AFM with TERS for Nanoscale Chemical Analysis
The Bruker Innova-IRIS (Integrated AFM-Raman Imaging System) combines tip-enhanced Raman spectroscopy (TERS) with AFM (Atomic Force Microscopy) and Raman spectroscopy.
This provides researchers with chemical or crystallographic information at high spatial and spectral resolution, together with advanced atomic force microscopy characterisation.
The Innova-IRIS integrates seamlessly with the Renishaw InVia for correlated micro- and nanoscale property mapping. Each system is still available to use separately with full capabilities.
The information provided by AFM and Raman spectroscopy is highly complementary:
AFM excels at high spatial resolution (even atomic resolution) surface structure, nano-mechanical information (adhesion, stiffness), and nano-scale electrical property maps including electric field gradients, work-function, conductivity and conductive AFM.
Meanwhile, the vibrational spectroscopic signature revealed by a Raman spectrum enables the detection and orientation of chemical bonds to create chemical maps.
Co-located AFM-Raman studies provide correlated information for pinpointing nano-scale chemistry-property relationships in chemically heterogeneous samples, from inorganic to polymers.
The development of Tip Enhanced Raman Spectroscopy (TERS) is an active area of research, holding the key to nanoscale chemical mapping. Based on utilising a plasmonics structure as near field antenna, TERS requires specialised tips. The small signals generated by the sampling volumes require AFM optical access optimised for near field coupling (i.e. side access for opaque samples, bottom access for transparent samples) as well as an extremely stable AFM platform to accommodate Raman integration times and preserve the tip. Bruker Innova-IRIS is designed to work with leading Raman instruments, and has been used for TERS research involving nanocrystals, biomolecules and thin molecular films.
Carbon Elemental Allotropes
Since carbon nanotubes and graphene were first discovered, their distinctive electrical properties and electronic structure has been the object of much interest and research. Combined AFM and Raman can observe individual carbon nanotubes and graphene flakes, precisely identifying structural parameters such as the number of graphene layers. It is possible to correlate graphene electronic structure revealed in the Raman G (graphite) and D/2D (defect) bands with nanoscale mechanical and electrical variations (for example, stiffness and work-function). This addresses questions of property tunability for device applications and sensitivity to electrical and chemical environment, relevant to potential sensing applications.
Nanoscale structure influences material properties, and can be characterised by mapping of nanoscale structure, properties, and chemistry, and correlating data from confocal Raman spectroscopy, TERS and advanced AFM modes such as Kelvin probe force microscopy (KPFM). This technique is useful when studying microphase structure in polymers, with end applications ranging from structural material to bulk heterojunction OPVs, the relation of electronic structure and properties to defects and chemical environment in graphene, crystallography and optical properties of nanocrystals, and thin molecular layers at interfaces.
Easy-to-Use AFM for Spectroscopy in Nanostructured Materials
- Ergonomic hardware and streamlined software
- Integrated set-up diagnostics
- Instant research quality results
- “Experiment Selector” distills decades of expertise from a complex field into preconfigured settings
Complete AFM Capabilities
- Full-featured suite of advanced topographic, electrical, mechanical and thermal AFM techniques
- Correlated property mapping for each AFM mode
- Noise and drift elimination for high-resolution imaging and long Raman integration times
True Nanoscale Spectroscopy
- Modular accessories for specific applications
- Optimised optical access to capture weak Raman signals for nanoscale chemical mapping, even on challenging samples
Complete TERS Solution
Innova-IRIS uses high-contrast IRIS TERS probes, only available from Bruker, for a complete solution with high sensitivity and spatial resolution.