It was recalled that Si impurities in diamond led to the appearance of a well-known system of 12 lines around 1.681eV; thought to arise from the Si-vacancy complex. This system was produced by various treatments suggestive of other Si-related centers in the material. In order to elucidate the possible structures of Si in diamond, first-principles calculations were performed. It was shown that interstitial Si was unstable at growth temperatures, that substitutional Si was probably visible only via vibrational mode spectroscopy, and that complexes of Si with lattice vacancies were electrically, paramagnetically and optically active. In addition, Si-N and Si-H complexes were considered within the context of doping and the KUL3 electron paramagnetic resonance center, respectively.

Density Functional Simulations of Silicon-Containing Point Defects in Diamond. J.P.Goss, P.R.Briddon, M.J.Shaw: Physical Review B, 2007, 76[7], 075204 (11pp)