New visible luminescence spectra from synthetic type IIa diamond

Abstract Two luminescence bands with new features different from the “band A” emission are found at 2·10 and 2·44 eV in a high-pressure synthetic diamond by interband photoexcitations in the indirect-edge absorption region. The temperature dependence, injection power dependence, growth and decay of these bands and thermoluminescence are studied. On the basis of these results, the 2·10eV band is assigned to the donor-acceptor-like recombination of close pairs and the 2·44 eV band is due to the recombination of free holes and trapped electrons at deep donors. The thermal activation energy of the acceptor-like state responsible for the 2·44 eV band is estimated to the 0·25 eV from the analysis of the thermoluminescence glow curve.