Photoluminescence in platinum doped GaN

An epitaxial GaN layer was doped with the radioactive isotope 191Pt by ion implantation at the online mass separator facility ISOLDE at CERN (energy 60 keV, maximum dose of 3x1012 ions/cm2). The isotope 191Pt decays with a half-life of 2.9 d into stable 191Ir. After annealing at 1300 K several Pt-related photoluminescence transitions in the near-infrared region are detected. Platinum is found to produce near-infrared luminescence consisting of two single transitions (Pt1) at 1.461 and 1.446 eV followed by a set of transitions (Pt2) starting at 1.273 eV each separated by 15 meV in energy. The photoluminescence spectra recorded within 30 days after implantation will be presented. The half-lives resulting from exponential fits to the intensities of these optical transitions yield half-lives of t1/2(Pt1)=(2.6±0.6) d and t1/2(Pt2)=(3.1±0.3) d, respectively, in very good agreement with the nuclear half-life of the isotope 191Pt. Therefore, the recombination centers responsible for this near-infrared luminescence have to involve exactly one Pt atom. We do not observe any other changes in the whole spectral region between 0.9 up to 3.5 eV, in particular no new lines turn up, so we conclude that iridium does not introduce any optically active recombination centers in GaN