Luminescence centers in Y3Al5O12:La single crystals

Abstract

The nature of luminescence centers created by La3+ isoelectronic impurities (IIs) in Y3Al5O12 (YAG) crystals has been considered. The La3+ dopant in YAG crystals gives rise to intensive UV luminescence in the complex band peaked at 4.28 eV at 300 K with a decay time of the main component of 575 ns. It has been shown that the complex UV emission band in YAG:La crystals in the 10–300 K range is a superposition of the luminescence of excitons localized near La dopants (LE(La) centers), the recombination luminescence of La3+ ions in the positions of Y3+ cations (LaY centers) and the low-intensive recombination luminescence of YAl antisite defects in the bands peaked at 4.65–4.62, 4.29–4.25 and 3.86–3.84 eV, respectively. In the visible range the emission spectra of YAG:La crystals also consist of the luminescence of F+ and F-centers in the bands peaked at 3.1 and 2.69 eV with a decay time of the main components of 2.3 ns and in the μs-ms range, respectively. It has been shown that the luminescence of F+ and F-centers in YAG:La crystals can be excited by emission of LE(LaY) and LaY centers.