Characterization of the broad green band luminescence in CVD and syntheticIb diamond

Results of photoluminescence (PL) and PL excitation (PLE) measurements on t he broad green band in CVD and synthetic Ib diamond are reported. PLE spect ra show that the green band in CVD diamond films is composed of two compone nts. The first component correlates with the a-C content and is attributed to recombination in amorphous carbon. The second component increases with s urface hydrogenation in CVD films, but remains almost unchanged in Ib diamo nd. On the basis of excitation and temperature dependencies of PL, the seco nd band is ascribed to the donor-acceptor pair recombination. The photoioni zation threshold for the transition from the valence band to the donor is f ound to be 3.25 eV. (C) 2000 Elsevier Science S.A. All rights reserved.