Synthesis and optical properties of Tb3+ or Dy3+-doped MgAl2O4 transparent ceramics

Abstract

MgAl2O4 ceramics doped with rare earth ions (Tb3+ and Dy3+ ions) were fabricated by SPS technique. Optical properties and pulse cathodoluminescence (PCL) spectra were studied. The redshift effect of the absorption boundary for rare earth (RE) ions doped ceramics was shown. It was shown that cathodoluminescence spectra in nanosecond time range can be decomposed into several emission bands at 2.72, 3.01, 3.37, 3.63 eV caused by F-type centers. It has been demonstrated that the introduction of terbium and dysprosium ions practically does not change the intensity ratio of the bands at 2.72, 3.01, 3.37 eV, but leads to an increase in the band at 3.63 eV in nanosecond time range. There are emission bands related to intrinsic host defects, RE ions dopants (Dy3+, Tb3+), and trace elements (Cr3+ ions) in PCL spectra measured in millisecond time range. The dependences of kinetic characteristics of spinel ceramics were studied. In nanosecond time range, decay kinetics of the MAS ceramics is described by the sum of two exponentials with luminescence decay times are 30 ± 5 ns and 0.8 ± 0.1 μs In the millisecond time interval, the luminescence decay time depends on the dopant ions.