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(如氧化铟锌)的缺陷掺杂和界面结构的基本了解。基于非晶态金属氧化物的薄膜晶体管(TFT)提供了透明电子的前景，以及相对于非晶硅和有机替代品的显著性能和工艺优势。基于氧化物的透明TFT器件技术的发展速度加快，但关于本征缺陷掺杂和非晶态金属氧化物半导体及其氧化物/介电界面的纳米级结构等关键/限制基础材料问题仍然知之甚少。目前，氧化物电子学文献对有关低载流子浓度区载流子迁移率和产生的关键问题没有报道，而关于氧化物沟道TFT器件的稳定性的报道很少，例如阈值电压漂移和沟道电导。在本项目中，将使用栅压测试-TFT器件来分析场效应输运行为作为沟道和栅极材料的加工和化学的函数。微观结构表征工具，如高分辨率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涨落显微镜将提供对非晶相的近程和中期结构的洞察。电子表征，如场效应传输和霍尔测量将被用来洞察加工对点缺陷尺度特征的影响。将使用一种新的缺陷体积测量方法来研究对本征施主缺陷结构和形成的洞察，该方法将薄膜应力与可测量的载流子密度变化联系起来。非技术性：该项目解决了材料科学中具有高度技术相关性的热门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，该材料可能会在显示器、传感器、智能窗和光伏等低成本、大面积电子产品中找到应用。该项目为研究生和本科生提供跨学科研究方面的培训。PI与当地行业的紧密联系将进一步提升学生专业培训体验的价值。该项目还包括对当地学校的教育推广活动，如中学生科学日和透明薄膜晶体管的实际操作演示。

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.