Analysis of structural disorder on Raman spectra of semiconductors

Abstract

This Tutorial provides a fundamental discussion on the lattice dynamics of physical systems introduced with disorder and, hence, the importance of Raman spectroscopy (RS) technique to probe these impacts. The article first discusses, analytically, the impact of disorder on the symmetry allowed phonon modes of the system by considering the finite probability of discrete-continuum interference in terms of electron–phonon interactions in the system, thereby briefly discussing the relevant experimental reports, followed by providing an ephemeral description on the loss of translational symmetry in the lattice environment under the strain field generated due to disorder and its consequence as relaxation of the q → = 0 selection rule in terms of RS; thus, correlating these discussions with the observation of the symmetry-forbidden disorder induced phonon modes. The same is also elaborated with the experimental reports on various systems of ABO3 and AO2 kinds, where A and B are cations that exhibit the occurrence of disorder induced phonon modes in the respective Raman spectra because of the disorder introduced into the host lattice, and which is emphasized to be not originating due to any structural phase transitions.