Precise estimation of doping-dependent Raman effect in inorganic solids

Abstract

Here we solve the problem of estimating the Raman frequency shift and the changes to Raman peak intensity due to doping (or changing chemical composition) and temperature consistently. The formalism employed to derive the temperature and doping-dependent Raman intensity ratio [or the ionization energy theory (IET)-based Raman intensity ratio] formula is based on the IET and the energy-level spacing renormalization group method. Therefore, our formalism is entirely based on first principles that does not require any guessed wavefunction nor intrinsic adjustable parameter anywhere in our analysis. The IET-Raman theory is then applied to Si(111), CdS, CdSe, \(\text{Cd}_{1-x}\text{Ca}_x\text{TiO}_3\) and 6H–SiC in order to expose the changes observed in the Raman spectra with respect to their peak intensity and frequency shift. We shall prove and highlight that the experimental Raman spectra obtained for the above-stated materials obey the physicochemical mechanism derived from the IET-Raman intensity formula unambiguously and without any exception. It is worth noting that the said formula can be implemented in all Raman spectroscopy machines as an additional feature to predict the Raman frequency shift and the Raman peak intensity with respect to temperature and changing chemical composition.

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