Photoluminescence spectra of Er3+-doped MgAl2S4 and CaAl2S4 single crystals

MgAl2S4, CaAl2S4, MgAl2S4:Er3+ and CaAl2S4:Er3+ single crystals were grown by the chemical transport reaction method. The single crystals crystallized in an orthorhombic structure. The single crystals had the direct energy ha nd structure and their optical energy gaps were 4.334 eV, 4.213 eV, 4.835 e V and 4.716 eV for the MgAl2S4, MgAl2S4:Er3+. CaAl2S4, and CaAl2S4:Er3+ sin gle crystals. respectively, at 13 Ii. Sharp emission peaks appeared in the MgAl2S4:Er3+ and CaAl2S4:Er3+ single crystals, and they were interpreted to originate from the Er3+ ion substituted Mg2+ and Ca2+ ions in the MgAl2S4: Er3+ and CaAl2S4:Er3+ single crystals.