Application of Raman imaging and scanning electron microscopy techniques for the advanced characterization of geological samples

Abstract

Raman is an important tool for diagnosing minerals in geoscience. However, smaller magnification of optical microscope assembled in conventional Raman spectroscopy limits the application of Raman in sub-micro and nano scale. Raman imaging and scanning electron microscopy (RISE) combine the advantage of scanning electron microscope and Raman spectroscopy, which can collect the morphology, composition, and structure information in the same micro region of the geological sample in situ. In this paper, we introduce the development and working mechanism of RISE, and carried out some typical applications in different research of geoscience. The purpose of this review is to allow readers to understand the basic principles and application potential of RISE in geoscience. Finally, we briefly point out current challenges faced by this technology and some research directions in the future. Highlights• Raman imaging and scanning electron microscopy as potential method was proposed for the research on geosciences.• Common polymorphism and isomorphism were distinguished clearly in situ.• A new research route for tiny inclusion and organic matter in situ was developed.

Morphological, Microstructural, and In Situ Chemical Characteristics of Siderite Produced by Iron-Reducing Bacteria

“…29 The RI-SEM system consists of a Zeiss (Germany) field scanning electron microscope (Gemini 450) with an acceleration voltage range of 0.02−30 kV and a highly sensitive WITec (alpha 300R, Germany) confocal Raman microscope. 30 Microchemical analyses were made by SEM with energydispersive X-ray spectrometry (EDXS). In situ focused ion beam (FIB)-milling sample preparation for TEM was performed with a Zeiss Auriga Compact dual beam FIB-SEM system.…”

“…The dried samples were mounted onto the surface of glass slides for SEM and RI-SEM analyses, carbon-coated copper grids for TEM analyses, and silicon nitride windows for synchrotron-based STXM analyses . The RI-SEM system consists of a Zeiss (Germany) field scanning electron microscope (Gemini 450) with an acceleration voltage range of 0.02–30 kV and a highly sensitive WITec (alpha 300R, Germany) confocal Raman microscope . Microchemical analyses were made by SEM with energy-dispersive X-ray spectrometry (EDXS).…”

Study on Sliding Surface Characteristics of Expansive Soil Based on Quantitative Evaluation of Microstructure

“…This system integrates an energy-dispersive X-ray spectroscopy (EDS) unit and the WITec alpha 300R confocal Raman microscopy system with the Zeiss Gemini 450 scanning electron microscope. This setup enables in-situ data collection for morphological, compositional, and structural analysis within the same microregion (Yuan et al 2022). After conducting gold sputter coating and applying conductive adhesive to the sample surface, the sample was placed into the SEM instrument for observation.…”

Feasibility of cell-phone camera Raman spectrometer for geological samples identification in field or mobile situations

“…The applications of Raman in micro-imaging are diverse and can be coupled with a wide range of complementary imaging instruments, like SEM, BSE, and EDS (i.e., Yuan et al, 2022). Obviously, the ability to combine Raman spectrometry with other methods has great advantages in terms of being able to use the molecular identification to confirm or disprove research questions that require comparison with other data types.…”