Native Point Defects, Electronically Active Impurities, and Plasmonics at ZnO Interfaces

技术描述：本研究项目探讨了使用原生点缺陷、简并掺杂和纳米结构来促进对ZnO界面上的接触整流、光子-等离子体耦合和纳米接触的理解。它建立在现有能力的基础上，利用光学和电子技术在纳米尺度上识别原生点缺陷的电活动，定量测量它们对载流子密度和原子掺杂浓度的影响，并利用纳米尺度表面科学技术可控地引入或抑制这些原生点缺陷。原生点缺陷对ZnO肖特基势垒高度有重要影响，它们与掺杂杂质的相互作用影响ZnO中的等离子共振波长。由于ZnO与金属表现出广泛的接触整流，因此可以在宏观和纳米尺度上测试通过ZnO-金属界面的热离子、隧道和跳变输运的相对贡献，并且物理机制的平衡可以用来理解各种化合物半导体结的电荷输运障碍。受原生点缺陷影响的载流子密度反过来会改变ZnO的介电响应，从而改变用于将光波耦合到超高频电子器件的等离子体共振频率。本项目采用生长、等离子体加工和原子扩散相结合的方法，在纳米尺度上控制近界面掺杂和原生点缺陷，以实现势垒整流和等离子体耦合。非技术描述：半导体缺陷是指在完美的半导体晶体中缺少原子或杂质等缺陷。它们具有电活性，可以改变在晶体管、激光器和其他电子设备内部自由流动的电荷量。它们也可以作为电荷穿过电子屏障的捷径，这些电子屏障通常是为了晶体管开关、电荷存储或载流子受限光发射而设计的。这些缺陷对电荷在ZnO界面上移动的影响为理解和控制其他半导体提供了一个测试平台，当这些材料首次用于电子产品时，这个问题就开始了。他们的控制可以实现透明电子产品的高载流子密度，如平视显示器和智能窗口，激光器的高正电荷密度，以及控制光波和电子电路之间的耦合，波长对电信很重要。该项目为研究生、本科生和高中女生提供基本的科学实验室技术和先进的微光电概念的培训。学生直接与瑞典奥斯陆大学、芬兰阿尔托大学和法国CNRS / CRHEA的国际合作者进行互动。该项目通过哥伦布女子学校的暑期研究实习项目，在美国国家科学基金会核心资金的基础上，得到俄亥俄州立大学几个机构的支持，参与并支持高中的女性。

Technical Description: This research project examines the use of native point defects, degenerate doping, and nanostructures to advance the understanding of contact rectification, photon-plasmon coupling, and nanocontacts at ZnO interfaces. It builds on existing capabilities to identify the electrical activity of native point defects on a nanometer scale using optical and electronic techniques, to measure their effect on carrier densities and atomic dopant concentrations quantitatively, and to controllably introduce or suppress these native point defects using nanoscale surface science techniques. Native point defects have a major effect on ZnO Schottky barrier heights, and their interplay with dopant impurities influence plasmonic-resonance wavelengths in ZnO. Because ZnO exhibits a wide range of contact rectification with metals, it can serve to test the relative contributions of thermionic, tunneling, and hopping transport through ZnO-metal interfaces on both a macroscopic and nanometer scale, and the balance of physical mechanisms can be used to understand barriers to charge transport for a wide range of compound semiconductor junctions. The carrier densities influenced by native point defects can in turn alter the dielectric response of ZnO and thus the plasmon-resonance frequency used to couple light waves to ultrahigh frequency electronics. This project employs a combination of growth, plasma processing, and atomic indiffusion to control near-interface doping and native point defects on a nanometer scale for both barrier rectification and plasmonic coupling.Non-technical Description: Semiconductor defects are imperfections such as missing atoms or impurities in otherwise perfect semiconductor crystals. They can be electrically-active, altering the amount of electrical charge free to travel inside transistors, lasers, and other electronic devices. They can also serve as shortcuts for charge to move through electronic barriers usually designed to block such charge movement for transistor switching, charge storage, or carrier confined light emission. The influence of these defects in charge movement across ZnO interfaces provides a test bed to understand and control other semiconductors, an issue starting when these materials were first used for electronics. Their control can enable high carrier densities for transparent electronics such as heads-up displays and smart windows, high positive charge densities for lasers, and control of the coupling between light waves and electronic circuits at wavelengths important for telecommunications. The project provides training of graduate students, undergraduates, and high school women in both basic scientific laboratory techniques and advanced micro- and optoelectronic concepts. Students interact directly with international collaborators at the University of Oslo, Sweden, Aalto University, Finland, and CNRS / CRHEA, France. The project involves and supports women at the high school through the Columbus School for Girls' summer research internship program, building on NSF core funding with support from several Ohio State University institutions.