EAPSI: In situ Structural Characterization of Lead-free, Bismuth-based Piezoelectric Thin Films

EAPSI：无铅、铋基压电薄膜的原位结构表征

• 批准号: 1713806
• 负责人: Austin Fox
• 金额: $ 0.54万
• 依托单位: Fox Austin
• 依托单位国家: 美国
• 项目类别: Fellowship Award
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-06-01 至 2018-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1713806&HistoricalAwards=false
• 关键词: EAPSI; situ; Structural; Characterization; Lead

There is a pressing need to discover and understand the behavior of environmentally benign, non-toxic, and sustainable replacements for lead-based materials in all applications (as already has been done for lead-based paints and solders). Suitable replacements have yet to be realized for piezoelectric materials (those that change shape with applied electric field and vice versa) that are important for a large range of devices and applications, such as actuators, accelerometers, filters, vibration control, fuel injection, ink jet printing, ultrasound generation and sensing, and resonators. One class of materials that shows great promise as replacements is based on bismuth sodium titanate (BNT). In thin films for microelectronic applications, the fundamental piezoelectric effect in these new materials is not yet understood well enough to allow devices to be reliably implemented. Accordingly, the objective of this project is to explore the mechanisms associated with piezoelectricity in BNT-based piezoelectric thin films using novel characterization methods available at Professor Hiroshi Funakubo's laboratory at the Tokyo Institute of Technology. Professor Funakubo's characterization tools allow for the measurement of atomic structure while applying electric fields, giving direct insight into the piezoelectric strain mechanisms of these exceptional materials.In bulk form, these BNT-based materials belong to a class of materials called relaxor ferroelectrics, which show enticing properties with regards to electric field induced displacement mechanisms that are just beginning to be understood. Many BNT-based compositions show the strain and polarization behavior that is characteristic of a reversible field-induced relaxor-to-ferroelectric phase transition; these are known as ergodic relaxors. However, BNT-based materials in thin film embodiments do not exhibit the enhanced properties that are found in the bulk. In particular, the ergodic relaxor compositions that have been studied in thin films do not show the signs of a reversible field-induced relaxor-to-ferroelectric phase transition, but rather behave similar to normal ferroelectrics and have comparatively low displacements. This differing response between bulk and thin films needs to be understood for this promising material system to be viable for real-world applications. Therefore, novel in situ microstructural characterization methods (2D X-ray diffraction and Raman spectroscopy), available at the host institution, will be applied to elucidate the electric field induced strain mechanisms in BNT-based piezoelectric thin films.This award under the East Asia and Pacific Summer Institutes program supports summer research by a U.S. graduate student and is jointly funded by NSF and the Japan Society for the Promotion of Science.

在所有应用中，针对铅基材料的环境良性，无毒和可持续的替代品的行为有迫切的需求（如已经针对铅基油漆和焊料所做的那样）。对于压电材料（使用施加的电场变化的材料（反之亦然的材料），对于多种设备和应用很重要的材料，例如执行器，加速度计，过滤器，振动控制，燃油喷射，燃油喷射，墨水喷射，超声打印，超声和传感器以及共振器，这尚未实现。一类显示出替代品的巨大希望的材料是基于二钛酸钠（BNT）的。在用于微电子应用的薄膜中，这些新材料中的基本压电效应尚未足够好，无法可靠地实施设备。因此，该项目的目的是使用在东京技术学院的Hiroshi Funakubo教授实验室获得的新颖特征方法探索与基于BNT的压电薄膜中与压电薄膜中的压电相关的机制。 Funakubo教授的表征工具可以在应用电场的同时测量原子结构，从而直接深入了解这些特殊材料的压力电离应变机制。在整体形式中，这些基于BNT的材料属于一种称为Lasheor Ferroelectrics的材料类别，这些材料属于电场引起的置换机械的诱人特性，这些材料仅是置换式的置换机制，这些材料正是从开始的，这就是开始的。许多基于BNT的组合物显示出可逆的场诱导的松弛器至有线相变的特征的应变和极化行为；这些被称为厄贡松弛剂。但是，薄膜实施方案中的基于BNT的材料并未表现出大量中发现的增强特性。特别是，已经在薄膜中研究的沿乳突松弛剂组成并未显示可逆的场诱导的宽松释放器至有效相位过渡的迹象，而是与正常的铁电相似，并且相似的位移相对较低。对于这种有希望的材料系统，需要了解大量和薄膜之间的这种不同的响应，这对于现实世界的应用是可行的。因此，在主机机构获得的新型原位微观结构特征方法（2D X射线衍射和拉曼光谱）将用于阐明基于BNT的压电薄膜中的电场诱导的应变机制。这是在美国和Pacific Summer Institutes计划下的Summer Instroops and Summer Instorm and Summer Soildion soparion Anderion Andivure and Iss Insed Fundirion and Fundirion and Inseff Fundirion and Ins Fundirion and Inse Fundirion and Inseff，这是基于BNT的Piezoelectric薄膜。该奖项。