Reactive sputtering of luminescent YAG:Ce thin films by dual hollow cathode plasma-jet

Cerium-doped yttrium aluminum garnet (Y 3 Al 5 O 12 :Ce, YAG:Ce) thin films were prepared by reactive co-sputtering from two separate elemental sources (Y 3 Al 5 alloy and pure cerium) using a dual hollow cathode plasma-jet system in an Ar/O 2 atmosphere. This plasma-based approach enabled spatial control of Ce incorporation through the geometric configuration of the sputtering sources and tailored power input. Film composition and structure were analyzed using LIBS, XRD, and optical methods, revealing a gradient in Ce content across the substrate array. Post-deposition annealing at 1000 °C was essential for crystallization and luminescence activation, resulting in the formation of single-phase YAG at low Ce concentrations and a gradual transition toward CeO 2 -rich films at high Ce loading. Photoluminescence and cathodoluminescence studies showed Ce 3+ emission at moderate doping levels, while higher Ce content led to phase segregation, Ce 4+ formation, and luminescence quenching. These results demonstrate that dual hollow cathode reactive sputtering provides a flexible approach for controlling the Ce distribution and for exploring the structural and optical behavior of YAG:Ce films under extreme Ce loading conditions. • Reactive sputtering of YAG:Ce thin films from metallic targets by two hollow cathodes • Ce concentration controlled by nozzle geometry and independent discharge powers • Post-annealed films show YAG:Ce crystallization and Ce 3+ luminescence activation • Demonstrated route for tunable luminescent garnet coatings for optical applications