Localized States, Chemical Reactions, and Charge Transport at ZnO Surfaces and Interfaces

技术上的。该项目涉及氧化锌表面和界面性质的基本方面，该方法包括：(A)最先进的氧化锌的受控生长，(B)使用补充的电子、光学和表面科学技术来表征表面、亚表面和体属性，(C)分析生长、表面处理和金属化的系统变化，以量化和识别缺陷和掺杂机制，以及(D)系统地反馈这些结果，以进一步优化生长和金属化过程。目标包括：(A)定量和识别氧化锌近表面施主和受主，(B)描述热离子发射、隧穿和缺陷辅助跳跃对氧化锌表面和界面内电荷输运的贡献；(C)建立一个自洽的电荷输运模型，用于计算氧化锌表面载流子浓度和跨越氧化锌-金属界面的肖特基势垒形成，该模型用于深度分辨阴极发光光谱、深能级瞬变光谱、电容-电压和电流-电压测量；(D)使用该模型来预测氧化锌的表面和金属界面输运性质；以及(E)建立该模型对其他化合物半导体的实用性。能够在纳米尺度上检测和分析表面、界面上的局域电子态性质以及它们在半导体块体中的扩展，有望揭示本征点缺陷、杂质和化学反应之间的相互作用，这些反应实质上改变了半导体空间电荷区的传统图景。该项目为预测界面电学性质提供了新的依据，为控制氧化锌光电接触和微电子接触铺平了道路。该项目涉及具有技术相关性的电子/光子材料科学专题领域的基础研究问题。了解和控制氧化锌表面和界面的电荷传输将使电子应用具有优势，例如用于节能白色照明和高容量DVD的紫外光发光二极管和激光二极管，以及用于显示器的透明晶体管。该项目还将把研究经验扩大到妇女和少数族裔大学本科生和当地高中的妇女，后者让哥伦布女子学校的学生在俄亥俄州立大学校园进行暑期研究。俄亥俄州立大学S工程学院和工程女性专业将分别为该项目提供资金和项目。该项目为学生提供了亲身体验实验室的重要机会，有机会进行可发表的研究，并一瞥科学研究中的兴奋和机会。

Technical. This project addresses fundamental aspects of surface and interface properties of ZnO The approach encompasses: (a) controlled growth of state-of-the-art ZnO, (b) characterization of surface, subsurface, and bulk properties using a complement of electronic, optical, and surface science techniques, (c) analysis of systematic variations with growth, surface treatment, and met-allization to quantify and identify defect and doping mechanisms, and (d) systematic feedback of these results to further refine both growth and metallization processes. Objectives include: (a) quantify and identify ZnO near-surface donors and acceptors, (b) describe the thermionic emis-sion, tunneling, and defect-assisted hopping contributions to charge transport within ZnO sur-faces and interfaces; (c) develop a self-consistent charge transport model for carrier concentra-tions within ZnO surfaces and Schottky barrier formation across ZnO-metal interfaces that ac-counts for the depth-resolved cathodoluminescence spectroscopy, deep level transient spectros-copy, capacitance-voltage, and current-voltage measurements quantitatively; (d) use this model to predict surface and metal-interface transport properties of ZnO; and (e) establish the utility of this model to other compound semiconductors. The ability to detect and analyze localized elec-tronic state properties at surfaces, interfaces and their extension into the semiconductor bulk on a nanometer scale is expected to reveal interplay between native point defects, impurities, and chemical reactions that substantially alter the conventional picture of the semiconductor space charge region. This project provides a new basis for predicting interface electronic properties that paves the way for controlling ZnO opto- and microelectronic contacts.Non-Technical. The project addresses fundamental research issues in a topical area of elec-tronic/photonic materials science having technological relevance. Understanding and controlling charge transport at ZnO surfaces and interfaces will enable electronic applications with benefits such as UV light-emitting diodes and laser diodes for energy-efficient white lighting and high capacity DVDs, and transparent transistors for displays. This project will also expand research experiences to women and minority university undergraduates and women from local high schools, the latter involving students from Columbus School for Girls in summer research on the OSU campus. OSU?s College of Engineering and Women in Engineering programs will augment this project with funding and programs, respectively. The project provides students with impor-tant opportunities for hands-on laboratory experience, a chance to do publishable research, and a glimpse of the excitement and opportunities in scientific research.