I have Raman data for thin films deposited under the same condition but that have undergone different post-deposition treatments. Along with peak shifts, there is a considerable change in peak intensity. What does the intensity indicate?
A number of factors may lead to this effect. If the mode belongs to single crystalline lattice than increase means that crystallinity increases, i.e. the size of crystallites grows. Oppositely, if the mode is forbidden in bulk crystalline lattice but allowed in small nanocrystals than its increase means decrease in crystallites size. Also, if direction of ions movement in the mode is unfavorable for excitation then increase of the mode means that the film undergoes reorientation that makes excitation stronger or emission more favorable for detection (in case of polarization sensitive detection channel.
A number of factors may lead to this effect. If the mode belongs to single crystalline lattice than increase means that crystallinity increases, i.e. the size of crystallites grows. Oppositely, if the mode is forbidden in bulk crystalline lattice but allowed in small nanocrystals than its increase means decrease in crystallites size. Also, if direction of ions movement in the mode is unfavorable for excitation then increase of the mode means that the film undergoes reorientation that makes excitation stronger or emission more favorable for detection (in case of polarization sensitive detection channel.
Completely agree with Aleksandr. It is also assumed that the expeimental conditions (laser power, acquisition time, objective were the same)
Assuming the post-deposition treatment is thermal, Aleksandr's first explanation is probably most applicable. Usually disorder/order also strongly affects the Raman linewidth, so you should try analyzing that as well (i.e. broader peaks can indicate inhomogeneous broadening). Line shape can also indicate which phonons away from the gamma point are contributing in the case of disordered systems. As for intensity, another mechanism that can enhance intensity is electronic transition resonance; if your treatment somehow shifted the band gap towards the laser energy, resonance Raman effect can change line intensities (though I suspect this is unlikely).
Hi sir. I am working with ions doped with the DNA. In case of Raman spectroscopy, as the concentration of ions increases, the intensity also increases. How can i interpret this data ?
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