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Persistent photoconductivity in titanate semiconductor crystals

钛酸盐半导体晶体的持久光电导性

基本信息

批准号：
2109334
负责人：
Matthew McCluskey
金额：
$ 39.67万
依托单位：
Washington State University
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2021
资助国家：
美国
起止时间：
2021-06-01 至 2024-05-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=2109334&HistoricalAwards=false
关键词：
Persistent photoconductivity titanate semiconductor crystals

项目摘要

Nontechnical description:The project investigates a novel phenomenon, persistent photoconductivity, which was recently observed at room temperature. Samples with this unique property experience a dramatic increase in electrical conductivity when exposed to light, which persists long after the light is turned off. Strontium titanate, a transparent crystal, exhibits large persistent photoconductivity at room temperature, opening possibilities for industrial applications ranging from optical memory devices to electroplating of metals on surfaces. The research team is attempting to characterize the defects that are responsible for this unusual behavior, maximize the size of the effect, and discover it in new materials. They use state-of-the-art facilities to grow novel crystals and study their physical properties. Students involved in this research perform hands-on experiments, present results at international conferences, and meet with startup companies to discuss potential applications. In conjunction with the optical theme of the research, lessons are developed for a required course for elementary education students seeking the middle science credential. These lessons on waves and light target the K–12 learning goals defined by the Next Generation Science Standards and Washington State Professional Educator Standards Board, Middle Level Science Endorsement Competencies.Technical description:The project aims to achieve large, room-temperature persistent photoconductivity in oxide semiconductors and exploit the phenomenon to advance knowledge about fundamental processes such as electronic transport. Kinetics, energy-barrier heights, and fundamental defect properties are investigated. These studies also elucidate the structure of hydrogen-related complexes in oxides. The research team is attempting to achieve large, room temperature persistent photoconductivity in barium titanate, a ferroelectric material that could exhibit larger conductivity changes than those previously discovered in strontium titanate. This unique phenomenon is exploited to investigate electrical properties, over a well-defined range of carrier concentrations, to provide insight into scattering mechanisms and small-polaron versus free-electron transport. Using unique facilities at Washington State University, crystals are grown with high purity and controlled defect populations. These crystals include solid solutions (alloys) that are designed to have optimal properties. A variety of experimental methods, including Hall effect, infrared spectroscopy, and photoluminescence, are used to study the persistent photoconductivity and the defects responsible for it. Besides providing fundamental insight, establishing defect and transport properties is important because it will allow researchers to control (i.e., induce and erase) and optimize the effect. The fundamental knowledge gained in this study could provide the basis for holographic storage, optically defined electronics, and selective electroplating.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

非技术描述：该项目研究了一种新现象，即最近在室温下观察到的持续光电导率。具有这种独特性质的样品在暴露于光下时电导率会急剧增加，这种情况在光线关闭后仍会持续很长时间。钛酸锶是一种透明晶体，在室温下表现出持久的大光导率，为从光存储设备到表面金属电镀等工业应用开辟了可能性。研究小组正试图描述导致这种不寻常行为的缺陷，最大化影响的大小，并在新材料中发现它。他们使用最先进的设备来培育新型晶体并研究其物理特性。参与这项研究的学生进行动手实验，在国际会议上展示结果，并与初创公司会面讨论潜在的应用。结合研究的光学主题，课程是为寻求中等科学证书的初等教育学生开发的必修课程。这些关于波和光的课程针对的是由下一代科学标准和华盛顿州专业教育工作者标准委员会定义的K-12学习目标，中等水平科学认可能力。技术描述：该项目旨在在氧化物半导体中实现大的、室温的持久光导性，并利用这种现象来推进对电子输运等基本过程的认识。动力学，能垒高度，和基本缺陷的性质进行了研究。这些研究还阐明了氧化物中氢相关配合物的结构。研究小组正试图在钛酸钡中实现大的室温持续光导性，钛酸钡是一种铁电材料，可以比以前在钛酸锶中发现的材料表现出更大的电导率变化。这种独特的现象被用来研究电学性质，在一个明确的载流子浓度范围内，为散射机制和小极化子与自由电子的传输提供见解。利用华盛顿州立大学的独特设施，晶体以高纯度和控制缺陷数量生长。这些晶体包括具有最佳性能的固溶体（合金）。各种实验方法，包括霍尔效应、红外光谱、光致发光，被用来研究持续的光电导率及其缺陷。除了提供基本的见解之外，建立缺陷和输运特性也很重要，因为它将使研究人员能够控制（即诱导和擦除）并优化效果。本研究获得的基础知识可为全息存储、光学定义电子学和选择性电镀提供基础。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

项目成果

期刊论文数量（4）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

Persistent optical phenomena in oxide semiconductors

氧化物半导体中的持久光学现象

DOI：
10.1117/12.2648437
发表时间：
2023
期刊：
Proc. SPIE
影响因子：
0
作者：
McCluskey, Matthew D.;Pansegrau, Christopher;Ahmed, Syeed E.;Santillan, Macarena;Jesenovec, Jani;McCloy, John S.
通讯作者：
McCloy, John S.

Room-Temperature Persistent Photoconductivity in Barium Calcium Titanate