2. Defects in materials and their detection by Raman spectroscopy

2.1 Various defects in solids

Defects in materials have a wide variety of origins, and are generally classified according to their dimension: point defects have dimension 0; defects appearing on lines have dimension 1; surface defects have dimension 2, and finally defects extending into the volume have dimension 3.

However, the size of the defect is no indication of its impact on the Raman spectrum. We'll see that defects that are a priori different in origin can in fact manifest themselves in the same way on the Raman spectrum.

There are several types of point defect. A first separation can be made between intrinsic defects (linked to the atoms of the original matrix) and extrinsic defects (linked to unintentionally introduced impurities...