In my study, all films were grown on the stibnite (polycrystalline) structure of Sb2S3. When I changed a parameter of a group of films, I observed that XRD peak intensities increased, while Raman peak intensities decreased. Although we repeated the analyses, we encountered the same results. What is the reason for the decrease in Raman peak intensities despite the increase in XRD peak intensities?
Remzi Aydın, your Sb2S3 films present an interesting puzzle between increased XRD peak intensity and decreased Raman peak intensity.
XRD reveals larger crystal domains, while Raman spectroscopy measures vibrational modes. Raman intensity decreases may indicate smaller domains, defects, or electronic structure changes, weakening specific modes.
For a more thorough knowledge of the material structure, use TEM or SEM to visualize grain size and morphology.
I hope this helps you. Best Regards.
One other thing you could consider is carrying out your Raman analysis in the transmission mode if you have not done so, this will give you a better bulk averaging of your sample. In the normal mode, Raman signals depends a lot on the orientation of your samples.
Raman-active vibrations weaken due to molecular structure changes, sample degradation leads to fewer Raman-active compounds, and molecular orientation changes affect Raman activity.
XRD intensity increases due to increased crystallinity, growth of larger crystallites, and changes in crystal structure, such as lattice parameter modifications, enhancing the diffracted signal.
Raman peak intensities are decreasing while X-ray diffraction (XRD) peak intensities are increasing, which can be attributed to various physical events related with these two analytical techniques.
Raman scattering is sensitive to molecular vibrations, providing information about chemical bonding, crystal structure, and molecular composition.
Factors that could lead to a decrease in Raman peak intensities include:
1. Fluorescence: If the material fluoresces, it can interfere with Raman signals, resulting in lower peak intensities.
2. Sample Decomposition: If the sample is susceptible to laser power or experiences chemical changes, the strength of the Raman signal may decrease.
XRD is based on the diffraction of X-rays by crystal lattices, providing information about the crystal structure, crystal orientation, and interatomic distances.
Factors that could lead to an increase in XRD peak intensities include:
1. Crystal Size: Smaller crystal sizes can result in broader XRD peaks with higher intensity due to increased contributions from smaller crystallites. 2. Preferred Orientation: If the crystals in the sample have a preferred orientation, it can lead to more intense XRD peaks. 3. Phase Purity: An increase in XRD peak intensity may be observed if the material becomes more phase-pure.
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