The National Institute of Standards and Technology (NIST) is working to establish Raman spectroscopy as a quantitative, SI-traceable technique for various applications including sensing, security, and forensics. Despite a century of development, Raman spectroscopy remains a qualitative technique due to the lack of traceable quantification and certified reference standards. NIST is collaborating with international partners to improve measurement reliability, establish traceability to SI units, and develop measurement protocols for consideration within the International Organization for Standardization (ISO).
The project focuses on advancing Raman spectroscopy for characterizing technologically important materials such as graphene and carbon nanotubes. By improving Raman spectroscopy, NIST aims to accelerate the development and commercialization of advanced electronics and photonics based on low-dimensional carbon materials for future information, communication, and sensor technologies. NIST has established a Technical Working Area (TWA) on Raman Spectroscopy and Microscopy within the Versailles Project on Advanced Materials and Standards (VAMAS) to enable multiple round-robin and interlaboratory comparison studies. Studies are currently underway for spectral calibration, spatial resolution, and composition differentiation.
NIST is also collaborating with other international organizations, including the International Committee for Weights and Measures (BIPM), to advance Raman spectroscopy. A separate TWA on Graphene and Related 2D Materials has joint projects with the Raman TWA, particularly focusing on the structural characterization of CVD-grown graphene. Other international work is ongoing under the BIPM, CCQM Working Group on Surface Analysis (CCQM-SAWG).
To improve the characterization of graphene and other 2D materials, NIST is working with researchers from Howard and Columbia Universities to develop rapid, quantitative techniques for assessing defect type and density. Crystals with varying defect types and densities, well-characterized by scanning tunneling microscopy/transition electron microscopy (STM/TEM), will be used to “benchmark” other techniques, including Raman spectroscopy. While Raman provides highly specific vibrational signatures for defects, its ability to distinguish different defect types remains limited. Strategies to address this include exploiting resonance effects to identify phonon anomalies as a function of defect type and density.
In addition to these efforts, NIST is collaborating with other universities and research institutions to advance Raman spectroscopy. These collaborations include the National Metrology Institutes, Towson University, Howard University, and Columbia University. By working together, these institutions aim to establish NIST as a unique resource for Raman spectroscopy and to advance the field of quantum standards.
Source: https://www.nist.gov/programs-projects/raman-metrology-and-instrumentation
Keywords: Nanocharacterization, Raman spectroscopy, Graphene
