Impurity optical absorption of Co2+-doped MgAl2S4 and CaAl2S4 single crystals

✍ Scribed by S.K. Oh; H.J. Song; W.T. Kim; H.G. Kim; C.I. Lee; T.Y. Park; M.S. Jin; C.S. Yoon

• Publisher: Elsevier Science
• Year: 2000
• Tongue: English
• Weight: 145 KB
• Volume: 61
• Category: Article
• ISSN: 0022-3697
• DOI: 10.1016/s0022-3697(99)00407-2

✦ Synopsis

MgAl 2 S 4 , CaAl 2 S 4 , MgAl 2 S 4 :Co 2ϩ , and CaAl 2 S 4 :Co 2ϩ single crystals were grown by the chemical transport reaction method. The single crystals crystallized into an orthorhombic structure. Optical energy gaps of the MgAl 2 S 4 , CaAl 2 S 4 , MgAl 2 S 4 :Co 2ϩ , and CaAl 2 S 4 :Co 2ϩ single crystals at 13 K were found to be 4.334, 4.835, 3.732, and 4.092 eV, respectively. Impurity optical absorption peaks were observed in the MgAl 2 S 4 :Co 2ϩ and CaAl 2 S 4 :Co 2ϩ single crystals. The impurity absorption peaks are thought to originate in electron transitions between energy levels of Co 2ϩ ions sited in T d symmetry in the MgAl 2 S 4 :Co 2ϩ and CaAl 2 S 4 :Co 2ϩ single crystals.