Photoluminescence spectra of Er~3+ -doped MgAl_2S_4 and CaAl_2S_4 single crystals

摘要

MgAl_2S_4, CaAl_2S_4, MgAl_2S_4: Er~3+ and CaAl_2S_4 : Er~3+ 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 band structure and their optical energy gaps were 4.334 eV 4.213 eV 4.835 eV and 4.716 eV for the MgAl_2S_4, MgAl_2S_4 : Er~3+, CaAl_2S_4, and CaAl_2S_4 : Er~3+ single crystals, respectively, at 13 K. Sharp emission peaks appeared in the MgAl_2S_4 : Er~3+ and CaAl_2S_4 : Er~3+ single crystals, and they were interpreted to originate from the Er~3+ ion substituted Mg~2+ and Ca~2+ ions in the MgAl_2S_4 : Er~3+ and CaAl_2S_4 : Er~3+ single crystals.