MULTIPLE-LOCALIZED-EXCITON SPECIES IN SULFIDE-DOPED AGBR DETECTED BY PHOTOLUMINESCENCE AND OPTICALLY DETECTED MAGNETIC-RESONANCE

The low-temperature photoluminescence of sulfide-doped AgBr has been examined with both steady-state and pulsed excitation. Prominent emission bands are observed at about 495, 566, 596, and 725 nm, depending upon excitation conditions. Sub-band-gap excitation peaks are observed at 464, 482, 496, 530, and 558 nm, depending upon monitoring wavelength. Excitation at 496 nm preferentially enhances the 596-nm emission that gives rise to an optically-detected-magnetic-resonance (ODMR) spectrum. ODMR data indicate that at least three species are contributing to the 596-nm emission. These species are interpreted as triplet excitons. A highly anisotropic species observed in the ODMR spectra is interpreted as a triplet exciton bound to a substitutional divalent sulfur-ion-interstitial-silver-ion complex with approximate [111] symmetry.