Substitutional site of Co2+ ions in single-crystalline AgGaS2:Co2+

Abstract

We investigated Co-doped AgGaS2 single crystals in order to determine the substitutional site of Co2+ ion in the crystal. The analysis of the absorption spectra shows that the Co2+ ions are located at the Ga sites and yields the values of the crystal-field parameter Dq = 359 cm(-1) and Racah parameter B = 605 cm(-1). The lattice constants of Co-doped crystals were almost the same as those of undoped ones. All the Raman modes were observed to soften in the Co-doped crystals, and that also implies the Co2+ ions occupy the Ga sites.