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

Abstract

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 Lu_1−xGd_xAlO₃ 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 Lu_1−xGd_xAlO₃: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 α-particles excitation. The Gd³⁺ → Eu³⁺ and Tb³⁺ → Eu³⁺ energy transfer processes are observed in Lu_1−xGd_xAlO₃ 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 α-particles is found only in YAlO₃:Eu, Lu_0.5Gd_0.5AlO₃: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.