Epitaxial growth of single crystalline film scintillating screens based on Eu3+ doped RAlO3 (R = Y, Lu, Gd, Tb) perovskites

The study is dedicated to the development of scintillating screens for microimaging applications based on the single crystalline films (SCFs) of Eu3+-doped (Y, Lu, Gd, Tb) AlO3-mixed perovskites grown onto YAlO3 substrates using the liquid phase epitaxy (LPE) method with the objective to optimize their X-ray stopping power and light yield. We confirm that the Eu3+-doped YAlO3 and TbAlO3 SCFs and full set of Lu1-xGdxAlO3 SCFs with x values in the x = 0-1.0 range can be crystallized on YAlO3 substrates using the LPE technique. The structural quality of films was studied using X-ray diffraction. The optical properties of Lu1-xGdxAlO3: Eu (x = 0-1) SCFs and TbAlO3: Eu mixed perovskites were also studied in this work in comparison with YAlO3: Eu SCF counterpart using the absorption, cathodoluminescence, photoluminescence (PL) emission and excitation spectra and PL decay kinetics as well as light yield measurements under e-beam and alpha-particles excitation. The Gd3+-> Eu3+ and Tb3+-> Eu3+ energy transfer processes are observed in Lu1-xGdxAlO3 and TbAlO3: Eu SCFs, respectively, increasing the efficiency of the Eu3+ luminescence in the perovskite hosts. Meanwhile, the highest light yield of the cathodoluminescence (CL) and radioluminescence (RL) under excitation by alpha-particles is found only in YAlO3: Eu, Lu0.5Gd0.5AlO3: Eu and GdAlO3: Eu SCFs. The light yield of CL and RL of these SCFs is notably higher than that in TbAlO3: Eu and LuAlO3: Eu SCFs and they even slightly (9-11%) overcome the light yield of the conventional Gd3Ga5O12: Eu SCF screens that are used in the microimaging detectors.