Stress-induced changes in the lattice dynamics strongly affect the proton transport in perovskites. Phonon softening as a result of tensile stress is expected to enhance the proton conductivity in yttrium-doped barium zirconate (BZY) thin films. Vibrational properties of materials are extensively studied by Raman spectroscopy. However, the sensitivity of Raman scattering in BZY films is low. Surface-enhanced Raman spectroscopy can characterize the vibrational motions of nanomaterials through the amplification of electromagnetic fields generated by the excitation of localized surface plasmons. In this work, we use commercial Ag nanowires to enhance the Raman signal and successfully measure the Raman spectra of BZY thin films. Qualitative analysis to the spectra from films with three different thicknesses allows us to resolve the difference between phonon frequencies of highly textured film and less textured polycrystalline films. We found that a highly textured film with preferred (100) orientation under tensile stress exhibits phonon softening with lower Zr–O stretching vibration energy. This work enables future investigation on the stress-induced phonon-assisted proton transport in thin films.

中文翻译：

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表面增强拉曼散射光谱揭示了钇掺杂锆酸钡薄膜的声子软化

应力引起的晶格动力学变化强烈影响钙钛矿中的质子传输。由于张应力导致的声子软化预计会增强钇掺杂的锆酸钡 (BZY) 薄膜中的质子传导性。材料的振动特性通过拉曼光谱进行了广泛的研究。然而，BZY 薄膜中拉曼散射的灵敏度较低。表面增强拉曼光谱可以通过放大由局部表面等离子体激发产生的电磁场来表征纳米材料的振动运动。在这项工作中，我们使用商业银纳米线来增强拉曼信号并成功测量 BZY 薄膜的拉曼光谱。对三种不同厚度薄膜的光谱进行定性分析使我们能够解决高纹理薄膜和纹理较少的多晶薄膜的声子频率之间的差异。我们发现在拉伸应力下具有优选 (100) 取向的高度织构薄膜表现出声子软化和较低的 Zr-O 拉伸振动能量。这项工作使未来对薄膜中应力诱导的声子辅助质子传输的研究成为可能。