| Title |
Optical Properties of Undoped and Ni^{2+} -doped MgIn_2Se_4 Single Crystals |
| Authors |
김형곤(Kim, Hyeong-Gon) ; 김병철(Kim, Byeong-Cheol) ; 신석두(Sin, Seok-Du) ; 김덕태(Kim, Deok-Tae) ; 최영일(Choe, Yeong-Il) ; 김남오(Kim, Nam-O) |
| Keywords |
결정구조 ; 광흡수 ; 광발광 MgIn_2Se_4 and MgIn_2Se_4 : Ni^{2+} ; Crystal structure ; Optical absorption ; Photoluminescence |
| Abstract |
MgIn_2Se_4 and MgIn_2Se_4 : Ni^{2+} single crystals were grown in the rhombohedral structure by the chemical transport reaction (C.T.R.) method using iodine as a transport agent. The optical absorption measured near the fundamental band edge showed that the optical energy band structure of these compounds had a direct band gap. The fundamental absorption band edge of these single crystals shift to a shorter wavelength region by decreasing temperature and the temperature dependence of the optical energy gaps in these compounds satisfy Varshni equation. The impurity optical absorption peaks due to nickel are observed in MgIn_2Se_4 and MgIn_2Se_4 : Ni^{2+} single crystal. These impurity optical absorption peaks can be attributed to the electronic transitions between the split energy levels of Ni_{2+} ions located at T_d symmetry site of MgIn_2Se_4 host lattice. In the hotoluminescence spectrum of the single crystal at 10 K, a blue emission with a peak at 687nm and a green emission with a peak at 815nm for the MgIn_2Se_4 single crystal were observed. |