ИСТИНА

Yttrium and lutetium garnet single crystals doped with Ce3+ are known as fast scintillators with high light yield. The band-gap engineering with Ga-doping and the partial or complete substitution of Lu and Y cations with Gd resulted in significant improvement of their scintillation properties. However, the presence of antisite defects in garnets is an inevitable consequence of the high growth temperature of the bulk crystals. The growth of single crystalline films using the liquid phase epitaxy method avoids the creation of antisite defects in the garnets structure, obtaining films with scintillation performance not worse than that for the single crystals. Here we report on the growth, optical and luminescence characterization of Ce3+ – doped Gd3(AlxGa1-x)5O12 (x=0.00, 0.22, 0.31, 0.38) single crystalline films. The quantitative chemical analyses of films were performed using electron-ion scanning microscope «QUANTA 3 D FEG» and scanning electron microscope Quanta 600 FEG. Transmission spectra were measured using Perkin Elmer Lambda 900 spectrophotometer. The luminescence characteristics as well as the reflectivity were measured using synchrotron radiation at the beamlines I (SUPERLUMI station) and BW3 at DESY (Hamburg) and at the branch-line FINEST at MAX-lab, Lund. Ce3+ - related luminescence has been observed in the case of partial substitution of Ga with Al ions. The effect is connected with the shift of 5d Ce levels to the bandgap. Experimental evidence of the bandgap increase with the introduction of Al3+ ions into gadolinium gallium garnet is presented as well.