Mn-Doped XAlO3 (X = Y, Tb) Single-Crystalline Films Grown onto YAlO3 Substrates: Raman Spectroscopy Study toward Visualization of Mechanical Stress

Wioletta Dewo,Yurii Syrotych,Tomasz Runka,Vitaliy Gorbenko,Yuriy Zorenko

doi:10.1021/acs.jpcc.1c03922

Abstract

Single-crystalline films (SCFs) of perovskites TbAlO3 (TbAP) and YAlO3 (YAP) doped with Mn ions were grown using the liquid-phase epitaxy (LPE) method on YAlO3 single-crystal (SC) substrates and investigated using Raman spectroscopy. The cross-section of the above-mentioned epitaxial structures was probed to obtain Raman signals of TbAP:Mn, YAP:Mn SCFs, and the YAP SC substrate. The undisturbed Raman signals of TbAP:Mn and YAP:Mn were recorded. For the TbAP:Mn sample, due to the difference in lattice constants between the SCF and the substrate, significant changes in the Raman spectra were observed. Over the interface between the SCF and the substrate, called the transition layer, gradual changes in the Raman spectra were observed. The changes are connected with the replacement of Tb3+ ions with Y3+ cations and are manifested as shifts of the modes assigned to translational, librational, and internal vibrations. Angular-dependent measurements of polarized spectra allowed determination of the TbAP:Mn SCF orientation in the ac plane (010). High-resolution luminescence spectra confirmed electronic transition attributed to Tb3+ cations and Nd3+ trace impurities in the YAP substrate. The Raman map recorded for the region close to the transition layer showed a shift of the Raman band at 552 cm–1 (YAP) related to the changes in the lattice constants and mechanical stress.

Highlights

Intensive development of optoelectronics and quantum electronics in recent years has required the use of materials with various optical properties
Noteworthy in this context are oxide compounds that are used as active media for solid-state lasers, optical components for shaping and processing of the spectral characteristics of radiation, scintillators, and media for optical recording of information.[1−9] From among them, special attention should be paid to oxide materials doped with rare earth ions, assuming the perovskite structure.[1−6] The single-crystalline films (SCFs) of perovskites have found extensive applications as thin-film laser media,[10,11] scintillators for the radiation monitoring of α- and βparticles,[12,13] cathodoluminescence screens,[14,15] and screens for visualization of X-ray images with a high spatial resolution.[7,16]
The Raman spectroscopy investigation of the cross-section of the SCF/substrate for TbAP:Mn and YAP:Mn SCFs grown on the YAP substrate of the (010) orientation was carried out by polarization analysis of incident and scattered light, that is, the recorded spectra were polarized

Summary

INTRODUCTION

Intensive development of optoelectronics and quantum electronics in recent years has required the use of materials with various optical properties. 1%) misfit between the lattice constants of SCF and the substrate in contrary to the homoepitaxial growth of YAP:Mn SCF on the YAP substrate when the SCF/substrate lattice mismatch is negligible.[22,23] One of the most important physical problems concerning such composite materials is characterization of the transition layer which arises between TbAP SCF and the YAP substrate during the LPE growth process. Our studies of such epitaxial structures have confirmed the occurrence of mechanical stress over the transition layer. Expecting the mechanical stress in this region, we investigated its influence on vibrational and optical properties of the material investigated

EXPERIMENTAL SECTION

RESULTS AND DISCUSSION

CONCLUSIONS

■ REFERENCES