Effect of W and Mo co-doping on the photo- and thermally stimulated luminescence and defects creation processes in Gd3(Ga,Al)5O12:Ce crystals

TL;DR

This study investigates how co-doping Gd3(Ga,Al)5O12:Ce crystals with W and Mo affects their luminescence and defect processes, revealing significant changes in optical properties and defect-related traps.

Contribution

It provides new insights into the impact of W and Mo co-doping on luminescence characteristics and defect creation in Gd3(Ga,Al)5O12:Ce crystals, which was not previously explored.

Findings

W and Mo co-doping enhances intrinsic emission and trap densities.

Co-doping alters photoluminescence and TSL glow curves.

Defects related to W and Mo influence luminescence behavior.

Abstract

Photo- and thermally stimulated luminescence characteristics of Gd3(Ga,Al)5O12:Ce single crystals co-doped with W and Mo are investigated in the 85 - 510 K temperature range and compared with the corresponding characteristics of the undoped and Ce3+ - doped Gd3(Ga,Al)5O12 single crystals of similar composition. A strong effect of the W and Mo impurity ions appears in the photoluminescence spectra and temperature dependences of the photoluminescence intensity, afterglow intensity and decay kinetics, thermally stimulated luminescence (TSL) intensity and TSL glow curves, excitation spectra of the TSL glow curve peaks and activation energy of their creation. The obtained results are explained by the enhancement of the intrinsic emission contribution into the luminescence spectrum of Gd3(Ga,Al)5O12:Ce,W and Gd3(Ga,Al)5O12:Ce,Mo due to a large concentration of various W - and Mo - related electron traps in these crystals and, consequently, the O- - type hole centers, as well as intrinsic crystal lattice defects (e.g., cation vacancies needed for the excess positive charge compensation of the W6+ and Mo6+ ions). The influence of the co-doping with W and Mo ions on the scintillation characteristics of Gd3(Ga,Al)5O12:Ce is discussed.