The influence of point defects on the electronic structures and optical properties of 3C-SiC

Using first-principles calculations, we studied the formation energy of point defects in cubic silicon carbide (3C-SiC) and the influences of defects on its electronic band structure, density of states, and optical properties. We found that the formation energy of the interstitial defect is greater than that of the vacancy and antisite defect, with the Si interstitial defect having the highest formation energy. The electronic band structure and density of states have no bandgap due to the vacancy defect, interstitial defect, and Si antisite defect (Si atom occupies the position of C atom), while the changes due to the C antisite defect (C atom occupies the position of Si atom) are not significant. Depending on the type of defect, the optical properties change differently, with the vacancy defect having the most significant impact on the optical properties. The vacancy defect notably increases the optical conductivity, dielectric function, reflectivity, extinction coefficient, and refractive index in the low-energy region, indicating the potential application of 3C-SiC in the field of optoelectronic devices.