A narrow (few meV half-width) dip was observed at 1.682eV in the photo-current spectra from films grown by chemical vapour deposition. The shape of the dip matched that of the absorption line from the well-known 1.682eV Si-related center. However, optical absorption measurements showed that it could not be explained simply by absorption of light at the 1.682eV center. A similar pattern of narrow peaks was observed here in photo-current and absorption spectra for the interstitial-related 3H center and had been observed previously for the vacancy-related GR1-8 and ND1 lines. The phenomenon could be explained by suggesting the involvement of an electron transfer process. That is, electrons from the excited states of a given center were captured by the defects responsible for the background photo-current; thus photo-current inactivating the latter.

Photoelectrical Properties of the 1.682eV and 3H Centres in Diamond. K.Iakoubovskii, A.Stesmans: Physica B, 2001, 308-310, 585-8