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 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 α-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 α-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.