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This paper addresses the carbon co-doping of Ce-doped garnets, an efficient scintillation material and white light phosphor. The composition and the optical and scintillation properties of carbon-co-doped Y3Al5O12 (YAG) are studied at different cerium and carbon concentrations. YAG:Ce,C crystals were grown in the Ar + CO atmosphere from W crucibles. The carbon concentration reaches 0.5 atom %, but it does not affect the Ce distribution coefficient. The appearance and elimination of color centers are discussed in comparison to Ce-free YAG:C crystals. The tuning of cerium and carbon concentrations provides a light yield enhancement of up to 29 600 phot/MeV. The achieved enhancement may extend the application range of garnet-type phosphors and scintillators.

The feasibility to grow bulk La-GPS:Ce scintillation crystals by the Czochralski method using Mo crucibles has been reported.

Ce‐doped yttrium aluminum garnet (YAG) is among the efficient rare‐earth garnet scintillators and phosphors. Herein, a computational and experimental study of complex F‐type defect centers formed in YAG by doping with cerium and carbon is addressed. The formation energies determined by ab initio calculations of different defects and atomic chemical potentials in YAG:Ce,C are discussed in O‐poor and O‐rich conditions corresponding to the crystal growth under Ar+CO reducing atmosphere, and postgrowth annealing in air, respectively. It is shown that as‐grown crystals contain numerous positively charged defects responsible for F‐type center formation, whereas mainly negative‐charged defects are remained after the annealing in air. The negatively charged defects located nearby Ce luminescence center occupying Y site may stabilize cerium in the tetravalent state and promote a hole transport to this luminescence center. This describes a high scintillation efficiency of Ce,C‐doped garnets. Furthermore, YAG:C and YAG:Ce,C with a high carbon concentration, in addition to luminescence peaked at 400 ns ascribed to F+‐type centers, possess a fast luminescence peaked around 650 nm that may be attributed to the complex defect centers. These unveiled features of the luminescence process in rare‐earth garnets may contribute to the development of efficient luminescence materials.