The infrared (IR) and Raman spectra of eight substitutional carbon defects in silicon are computed at the quantum mechanical level by using a periodic supercell approach based on hybrid functionals, an all electron Gaussian type basis set and the CRYSTAL code. The single substitutional C s case and its combination with a vacancy (C sV and C sSiV) are considered first. The progressive saturation of the four bonds of a Si atom with C is then examined. The last set of defects consists of a chain of adjacent carbon atoms C, with i = 1–3. The simple substitutional case, C s, is the common first member of the three sets. All these defects show important, very characteristic features in their IR spectrum. One or two C related peaks dominate the spectra: at 596 cm−1 for C s (and C sSiV, the second neighbor vacancy is not shifting the C s peak), at 705 and 716 cm−1 for C sV, at 537 cm−1 for C and C (with additional peaks at 522, 655 and 689 for the latter only), at 607 and 624 cm−1, 601 and 643 cm−1, and 629 cm−1 for SiC, SiC, and SiC, respectively. Comparison with experiment allows to attribute many observed peaks to one of the C substitutional defects. Observed peaks above 720 cm−1 must be attributed to interstitial C or more complicated defects.

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mechanical infrared ir and raman spectra periodic supercell approach carbon defects substitutional c gaussian

Philippe D'Arco, Alexander Platonenko, Roberto Dovesi, Michel Rérat,Francesco S. Gentile, Khaled E. El‐Kelany,.Substitutional carbon defects in silicon: A quantum mechanical characterization through the infrared and Raman spectra. (),.

Philippe D'Arco, et al."Substitutional carbon defects in silicon: A quantum mechanical characterization through the infrared and Raman spectra"

Philippe D'Arco, Alexander Platonenko, Roberto Dovesi, Michel Rérat,Francesco S. Gentile, Khaled E. El‐Kelany,"Substitutional carbon defects in silicon: A quantum mechanical characterization through the infrared and Raman spectra"