Electrically and Optically Active Nonstoichiometric Metal Oxides

这项研究是麻省理工学院H·L·图勒教授非常富有成效的项目的继续。在国家科学基金会的支持下，Tuller教授和他的同事们在科学期刊上发表了18篇重要论文，主题包括非化学计量比氧化物的混合电导，多晶氧化锌晶界和界面的电子结构，稳定的钽氧化物中的缺陷和电荷输运，氧化镁和氧化铝的电学和光学性质，混合稀土和铀氧化物的热力学和输运特性，以及金属氧化物传感器。目前的研究将强调单晶和多晶形式的非化学计量金属氧化物中缺陷的形成、相互作用和传输。该计划将包括实验和理论工作。电活性陶瓷界面(构成各种先进电子设备的基础)将被研究，目的是改变和控制这些界面的化学成分，表征它们的电子传输特性，并解释两者之间的相关性。氧缺陷浓度将通过复阻抗技术和一种独特的基于光电化学腐蚀的新方法来确定。固体扩散技术将被用来确定氧离子构型作为组成的函数。电子陶瓷对半导体工业、传感器工业以及燃料电池、催化剂和高温电池具有重要的技术价值。对缺陷结构和电荷输运的了解对这些材料的性能至关重要。培训学生在这一关键领域进行研究是这一研究计划的关键部分。

This research is the continuation of a very productive program under Professor H. L. Tuller at the Massachusetts Institute of Technology. Under the prior support by the National Science Foundation, Professor Tuller and his colleagues published more than eighteen significant papers in scientific journals on topics such as mixed electrical conduction in nonstoichiometric oxides, electronic structure of grain boundaries and interfaces in polycrystalline zinc oxide, defects and charge transport in stabilized tantalum oxide, electrical and optical properties of magnesia and alumina, thermodynamics and transport properties in mixed cerium and uranium oxides, and metal oxide sensors. The current research will emphasize defect formation, interaction, and transport in nonstoichiometric metal oxides in both single and polycrystalline forms. The program will include both experimental and theoretical efforts. Electrically-active ceramic interfaces (which form the basis of a variety of advanced electronic devices) will be studied with the goal of modifying and controlling the chemistry of these interfaces, characterization of their electronic transport properties, and interpreting the correlation between the two. Oxygen defect concentration as a function of depth from the surface will be determined with complex impedance techniques and through a unique new method based upon photoelectrochemical etching. Solid state diffusional techniques will be used to establish the oxygen ion configuration as a function of composition. Electronic ceramics are technologically important to the semiconductor industry, the sensor industry, and for fuel cells, catalysts, and high temperature batteries. Understanding of the defect structure and electrical charge transport is crucial to the performance of these materials. Training of students to do research in this critical area is a key part of this research program.