Abstract
High resolution, low temperature photoluminescence spectra of manganese-doped willemite (Zn2SiO4:Mn) single crystals have been measured. “Hot” bands on the zero-phonon lines of the4T1excited state of MnZn2+on inequivalent sites are observed at low Mn concentration between 4 K and 29 K. Their appearance is attributed to vibronic (Ham) quenching of the first-order spin-orbit interaction in the4T1excited state, by analogy with known properties of MnZn2+ZnS and ZnSe. At higher Mn concentration, additional lines appear which are assigned to Mn pair centers involving substitution on nearest neighbor Zn sites. Electron microprobe analysis shows that the segregation coefficient of Mn incorporation in the crystal increases as the Mn concentration in the melt increases. This is indicative of pairwise incorporation during growth, and consistent with the optical detection of Mn pairs in the crystals at higher Mn concentrations. The measured luminescence decay times depend on both Mn concentration and temperature of the crystals, due to thermally activated energy transfer between Mn centers. © 1984, The Electrochemical Society, Inc. All rights reserved.