Photoluminescence decay times and quantum yields were measured at 77 K
in the spectra of two Si-doped diamond films grown by the chemical-va
por deposition technique. A decay time of 950 ps For both films and a
quantum yield of 0.05 for one film were determined for the Si center z
ero-phonon optical transition at 737 nm (1.6823 eV). Two broad subband
s with decay times of 55 and 650 ps and yields of 8x10(-4) were observ
ed in the luminescence at 600, 650, and 720 nm and ascribed to an sp(2
) nondiamond carbon phase.