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

技术。本项目研究ZnO表面和界面特性的基本方面。(a)控制最先进的ZnO的生长，(b)利用电子、光学和表面科学技术的补充来表征表面、亚表面和体性质，(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)系统反馈这些结果，以进一步完善生长和金属化过程。目标包括：(a)量化和识别ZnO近表面供体和受体，(b)描述热离子发射，隧道和缺陷辅助跳变对ZnO表面和界面内电荷传输的贡献；(c)建立了ZnO表面载流子浓度和ZnO-金属界面上肖特基势垒形成的自一致电荷输运模型，该模型定量地考虑了深度分辨阴极发光光谱、深能级瞬态光谱复制、电容电压和电流电压测量；(d)利用该模型预测ZnO的表面和金属界面输运性质；(e)建立该模型对其他化合物半导体的实用性。在纳米尺度上检测和分析表面、界面及其延伸到半导体体的局部电子状态特性的能力有望揭示原生点缺陷、杂质和化学反应之间的相互作用，这些化学反应实质上改变了半导体空间电荷区域的传统图像。该项目为预测界面电子特性提供了新的基础，为控制ZnO光电和微电子接触铺平了道路。本项目涉及电子/光子材料科学中具有技术相关性的主题领域的基础研究问题。了解和控制ZnO表面和界面上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展到女性和少数民族大学本科生以及当地高中的女性，后者包括哥伦布女子学校的学生在俄勒冈州立大学校园进行夏季研究。俄勒冈州立大学吗?工程学院和妇女工程项目将分别为该项目提供资金和项目。该项目为学生提供了实践实验室经验的重要机会，有机会进行可发表的研究，并瞥见了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.