Linear response calculation of first‐order Raman spectra of point defects in silicon carbide

Abstract

AbstractRaman spectroscopy has been increasingly used, in recent years, to characterize irradiated materials, in particular silicon carbide. The interpretation of the spectra is nevertheless problematic. In this paper, we provide a first step toward a more quantitative interpretation, by providing first‐principles calculations of Raman intensities for various polytypes of silicon carbide (SiC) and for point defects in cubic SiC. We consider here, as benchmarks, the carbon antisite, CSi, and the doubly charged carbon vacancy/carbon antisite complex, VC. We show that some care is necessary to understand the contribution of point defects on the Raman spectrum of the material, due to supercell size effects.Calculated Raman spectra of cubic SiC with and without point defect, here a carbon antisite, CSi, in a 216‐atom supercell.