Interstitial-carbon hydrogen interaction in silicon

The T-line luminescence system is created in Si by annealing at 400-600 degrees C. Shifts and splitting of the spectral features with C-13 and D isotope substitution identify the presence of two C atoms and one H atom in the center. Uniaxial stress and magnetic field measurements show that the T center has monoclinic I symmetry and possesses an acceptor (-/0) level at 0.2 eV below the conduction band. Ab initio cluster calculations lead to a structure in which an interstitial C-H defect binds with a substitutional C atom. The calculated vibrational modes are in good agreement with those observed.