Effect of some physical perturbations and their interplay on Raman spectral line shapes in silicon: A brief review

Raman spectroscopy is a proven versatile tool for characterization of materials spanning almost all areas of science because of its ability to non-invasively extract information about materials. This technique is able to detect any perturbation in a system that can affect the phonons. A detailed discussion on various factors that affect the Raman line shape for a material has been summarized here by taking the example of silicon. Methods to identify the actual reason(s) behind the observed Raman spectral line shape have also been briefly discussed. Raman line shape obtained from silicon nanostructures when analyzed closely along with their bulk counterparts, reveals important information about the quantum confinement in such systems characterized by the Bohr's exciton radius. Raman line-shape parameters are analyzed closely to understand the influence of any perturbation like quantum confinement, heavy doping, temperature rise, pressure, excitation wavelength, electron–phonon interaction, and so on. Current review briefly deals with the origin of asymmetric Raman line shapes in (nano-) silicon due to various physical perturbations and their interplays, which becomes the origin of different line shapes. Advantages of using Raman microscopy in analyzing subtler physical processes taking place in a semiconductor have also been underlined.