Photoluminescence study of annealed nickel- and nitrogen-containing synthetic diamond

The results of a photoluminescence (PL) study of synthetic diamonds showing different degrees of nickel-nitrogen complex transformation are presented. A number of new, previously undocumented PL systems with zero-phonon lines (ZPLs) at 2.071, 1.991, 1.940, 1.648 and 1.413 eV have been found. Most of the PL systems observed are transient, only the S2, S3, 1.563 and 1.648 eV systems are present in the PL spectra of crystals annealed at 2200 degrees C and 2500 degrees C. The photoluminescence excitation (PLE) spectra for the 2.071, 1.991, 1.704, 1.660, 1.563 and 1.648 eV systems have been measured. It has been established that vibronic bands with ZPLs at 2.427 and 1.991 eV seen in the absorption spectra of annealed diamonds are related to the 1.660 and 1.991 eV PL systems, respectively. It has been revealed that the well-known 1.4 eV system is present in the PL spectra of diamonds annealed at temperatures of 2200 degrees C and higher. (C) 1999 Elsevier Science S.A. All rights reserved.