Lithium diffusion in lithium tantalate as measured by confocal Raman spectroscopy
Lithium diffusion in lithium tantalate as measured by confocal Raman spectroscopy
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DOI：
10.1007/s10853-022-07105-y
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发表时间：
2022-03
影响因子：
4.5
通讯作者：
Jacob Ivy;G. Brennecka
中科院分区：
文献类型：
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作者：
Jacob Ivy;G. Brennecka
采用两级气相传输平衡 (VTE) 来缓解钽酸锂 (LiTaO3) 单晶中的锂缺陷。这项工作详细介绍了低温气相传输渗透 (VTI) 退火步骤，该步骤在处理过的样品中建立了富锂表面层，消除了同质 LiTaO3 的本征点缺陷复合物，同时允许在过程的不同阶段通过共焦拉曼光谱测量点缺陷的深度和浓度分布。然后使用这些数据计算 LiTaO3 中锂的扩散系数，其范围在 950 至 1100 °C 之间为 4.2 × 10-11 至 2.9 × 10-10cm2/s。锂梯度被移除，样品化学成分在环境大气中的第二次高温退火过程中达到平衡，并通过额外的拉曼测量进行确认。温度相关的阻抗谱数据也用于确认这些样品中是否存在锂梯度，并表明 LiTaO3 的锂化在低至 950 °C 的温度下发生。
A two-stage vapor transport equilibration (VTE) has been employed to mitigate lithium deficiency in single crystals of lithium tantalate, LiTaO3. This work details a low-temperature vapor transport infiltration (VTI) anneal step that establishes a lithium-rich surface layer in the treated samples which annihilates the intrinsic point defect complexes of congruent LiTaO3while allowing depth and concentration profiles of the point defects to be measured via confocal Raman spectroscopy at different stages in the process. These data are then used to calculate diffusion coefficients for lithium in LiTaO3, which range between 4.2 × 10-11and 2.9 × 10-10cm2/s between 950 and 1100 °C. The lithium gradients are removed, and sample chemistry is equilibrated during a second, higher-temperature anneal in an ambient atmosphere and confirmed via additional Raman measurements. Temperature-dependent impedance spectroscopy data are also used to confirm the presence or absence of lithium gradients in these samples and show that lithiation of LiTaO3takes place at temperatures as low as 950 °C.