Structure and Performance of High Mobility Amorphous Indium-Oxide-Based Materials for Transparent Thin Film Transistors

技术：本项目旨在促进对一类新兴的高迁移率半导体金属氧化物材料（如铟锌氧化物）的缺陷掺杂和界面结构的基本理解。基于非晶金属氧化物的薄膜晶体管（TFTs）与非晶硅和有机替代品相比，具有显著的性能和加工优势，有望实现透明电子器件。氧化物基透明TFT器件技术的发展速度加快，但关键/限制性基础材料问题，如天然缺陷掺杂和非晶金属氧化物半导体的纳米级结构及其氧化物/介电界面仍然知之甚少。目前，氧化物电子学文献对低载流子浓度下载流子迁移率和产生的关键问题保持沉默，对氧化物通道TFT器件的稳定性的报道也很少，例如，阈值电压位移和通道电导率。在这个项目中，将使用一个栅极下降测试tft装置来分析场效应输运行为作为通道和栅极材料加工和化学的函数。显微结构表征工具，如高分辨率透射电子显微镜将用于界面形貌评估，而电子散射和径向分布函数分析以及波动显微镜将提供对非晶相近中期结构的深入了解。电子表征，如场效应输运和霍尔测量将用于提供洞察处理对点缺陷尺度特征的影响。我们将使用一种新的缺陷体积测量方法来研究天然供体缺陷的结构和形成，该方法将薄膜应力与可测量的载流子密度变化联系起来。非技术：该项目涉及材料科学中具有高技术相关性的主题领域的基础研究问题，并有望提供对一类半导体氧化物材料的科学理解，这些材料可以用于低成本，大面积电子显示器，传感器，智能窗口和光伏。该项目为研究生和本科生提供跨学科研究方面的培训。学院与本地工业的紧密联系将进一步提升学生的专业培训经验的价值。该项目还包括在当地学校开展教育推广活动，如中学生科学日和适合年级的透明薄膜晶体管实践示范。

Technical: This project seeks to advance fundamental understanding of defect doping and interface structure of an emerging class of high-mobility semiconducting metal oxide materials, such as indium zinc oxide. Thin film transistors (TFTs) based on amorphous metal oxides offer the promise of transparent electronics along with significant performance and processing advantages over the amorphous Si and organic alternatives. The rate of development of oxide-based transparent TFT device technology has accelerated while critical/limiting underlying fundamental materials issues concerning native defect doping and the nano-scale structure of amorphous metal oxide semiconductors and their oxide/dielectric interfaces remain poorly understood. At present, the oxide-electronics literature is silent on critically important questions concerning carrier mobility and generation in the low carrier concentration regime and little is reported on the stability of oxide-channel TFT devices with respect to, for example, threshold voltage shift and channel conductivity. In this project, a gate-down test-TFT device will be used to analyze field effect transport behavior as a function of the processing and chemistry of channel and gate materials. Microstructural characterization tools such high resolution transmission electron microscopy will be used for interface morphology evaluation, while electron scattering and radial distribution function analysis along with fluctuation microscopy will provide insight into the near- and medium-range structure of the amorphous phase. Electronic characterization such as field effect transport and Hall measurements will be used to provide insight into the effect of processing on point-defect-scale features. Insights into the structure and formation of native donor defects will be examined using a novel defect volume measurement approach that relates film stress to measurable carrier density changes.Non-technical: The project addresses basic research issues in a topical area of materials science with high technological relevance, and is expected to provide scientific understanding of a class of semiconducting oxide materials, which could find applications for low cost, large-area electronics for displays, sensors, smart windows, and photovoltaics. The project provides training of both graduate and undergraduate students in research in an interdisciplinary. Strong connections between the PI and local industry will further enhance the value of the professional training experience for the students. The project also includes educational outreach activities to local schools, such as Science Day for middle school students and hands-on grade-appropriate demonstration of transparent thin film transistors.