Red luminescence in phosphorous-doped chemically vapor deposited diamond

Luminescence studies have been performed on phosphorous-doped diamond films deposited by hot-filament chemical vapor deposition. A broad luminescence band, centered around 1.9 eV is revealed, in the cathodo luminescence spectra of homoepitaxial and polycrystalline films, whereas the blue band-A luminescence, which is characteristic for undoped diamond, is quenched in the presence of phosphorus. The 1.9 eV luminescence band could not be excited by Ar+ laser light (2.54 eV) and did not show a zero-phonon line in the spectrum. Therefore, we suggest that this band is a red form of band-A luminescence, related to electron-hole recombination at substitutional phosphorous and a phosphorus-vacancy complex.