Tracer Diffusion in Proton-Exchanged Lithium Niobate

质子交换铌酸锂中的示踪扩散

基本信息

批准号：
398946619
负责人：
Professor Dr. Harald Schmidt
金额：
--
依托单位：
Institut für Metallurgie
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2018
资助国家：
德国
起止时间：
2017-12-31 至 2020-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/398946619?language=en
关键词：
Tracer Diffusion Proton Exchanged Lithium

项目摘要

Lithium niobate (LiNbO3) is one of the most technologically important materials for optical applications. Optical waveguides based on this material are a fundamental structure unit in building various photonic devices. The proton-exchange process has been found as an effective method of fabricating low-loss waveguides out of LiNbO3 crystals. During proton-exchange lithium is replaced by hydrogen at the surface during annealing of LiNbO3 in a hydrogen containing melt like benzoic acid at moderate temperatures (< 400 °C). Currently, the kinetic aspects of the formation of the hydrogen enriched zone are unknown and have to be understood on a fundamental way. This includes the knowledge of the tracer diffusivities of the individual Li and H ions and their mutual interplay for the determination of effective diffusivities governing the proton-exchange process. The aim of the present project is the determination of hydrogen and lithium tracer diffusivities in proton-exchanged LiNbO3 single crystals as a function of temperature below 500 °C and hydrogen concentration. For realization, two-step experiments will be done. First, a LiNbO3 single crystal will be proton-exchanged with the isotope 1H at a certain temperature. From this effective diffusivities governing proton-exchange will be extracted. Afterwards, stable 6Li and 2H tracers will be used to quantify diffusion in the 1H enriched zone. As tracer source 6LiNbO3 sputter layers and deuterated liquid benzoic acid will be used. Isotope depth profiles will be measured by Secondary Ion Mass Spectrometry (SIMS). The experiments will be carried out on congruent (48.5 mol% Li2O) and near-stoichiometric (about 50 mol% Li2O) LiNbO3 single crystals at different crystal orientations. The results will allow a comparison of diffusivities and activation energies for Li and H diffusion. In the framework of literature and based on these experimental data, a model will be presented to describe effective diffusivities governing the proton-exchange. The fundamental results gathered during the project should also contribute to optimized LiNbO3 device fabrication and performance.

Niobate锂（Linbo3）是光学应用中最重要的材料之一。基于该材料的光学波导是构建各种光子设备的基本结构单元。质子交换过程已被发现是从Linbo3晶体中制造低损失波导的有效方法。在质子交换期间，在含有中等温度（<400°C）的含熔体的氢气中，linbo3在linbo3退火过程中，锂在linbo3退火过程中取代。当前，富含氢的区域的形成的动力学方面尚不清楚，必须以基本方式理解。这包括对单个LI和H离子的示踪剂差异的了解及其相互互动，以确定质子交换过程的有效差异。本项目的目的是确定质子交换的LINBO3单晶的氢和锂示踪剂差异，这是温度低于500°C和氢浓度的函数。为了实现，将进行两步实验。首先，在一定温度下，Linbo3单晶将用同位素1H质子交换。从这种有效的差异来看，构造质子交换的差异将被提取。之后，稳定的6LI和2H示踪剂将用于量化1H富含区域中的扩散。将使用示踪剂源6BinblO3溅射层和氘化液体苯甲酸。同位素深度分布将通过次级离子质谱法（SIMS）测量。实验将以一致（48.5 mol％li2O）和近化学计量计（约50 mol％LI2O）LINBO3单晶在不同的晶体方向上进行。结果将允许比较LI和H扩散的不同才能性和激活能。在文献框架和基于这些实验数据的框架中，将提出一个模型来描述有关质子交换的有效差异。项目期间收集的基本结果也应有助于优化的Linbo3设备制造和性能。