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Substitutional carbon defects in silicon: A quantum mechanical characterization through the infrared and Raman spectra
Author(s) -
Gentile Francesco S.,
Platonenko Alexander,
ElKelany Khaled E.,
Rérat Michel,
D'Arco Philippe,
Dovesi Roberto
Publication year - 2020
Publication title -
journal of computational chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.907
H-Index - 188
eISSN - 1096-987X
pISSN - 0192-8651
DOI - 10.1002/jcc.26206
Subject(s) - vacancy defect , raman spectroscopy , silicon , atom (system on chip) , materials science , spectral line , crystallography , infrared , infrared spectroscopy , basis set , molecular physics , chemistry , computational chemistry , density functional theory , physics , optics , optoelectronics , organic chemistry , astronomy , computer science , embedded system
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 s V and C s SiV ) 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 Cs i , 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 s SiV , the second neighbor vacancy is not shifting the C s peak), at 705 and 716 cm −1 for C s V , at 537 cm −1 for Cs 2 and Cs 3 (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 SiCs 2 , SiCs 3 , and SiCs 4 , 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.