Synthesis and Characterization of Nanoscale Metal Oxide Heterostructures for Chemical Sensing

本计画的目标为：（1）扩充高品质氧化物半导体薄膜及p-n异质结构的成长与性质表征的基础知识：（2）系统地表征氧化物半导体薄膜及p-n异质结构的电输运性质与化学掺杂、薄膜厚度、外加偏压及温度的关系;（3）制造基于由场效应晶体管（FET）结构组成的外延单晶膜的模型系统，并发展对跨p-n结施加的偏压对电输运性质和选择性吸附性质的影响的基本理解;以及（4）探索诸如具有暴露的p-n结的双极晶体管的更复杂器件的制造和表征。这些器件提供了在暴露的p-n结的吸附放大的电子响应的可能性，这可能会提供一个新的水平的控制在原子和分子水平。长期的目标是发展的氧化物基半导体异质结构的基本理解，适用于纳米工程吸附剂，可调显示器，催化材料和化学传感器的设计。所获得的理解有望为提高化学选择性和灵敏度提供指导，并为选择性，可调化学传感微电子器件的发展提供科学基础。所获得的见解不仅有利于推进化学传感器技术和改善社会健康和安全，而且还将影响电子和光学设备透明电极的基础研究和技术开发。此外，通过与福特的合作，该项目将提供的基本信息可能会改善稀燃发动机的排放控制技术。因此，拟议研究的知识和更广泛的影响可能远远超出化学传感领域。该项目主要研究材料科学领域的基础材料研究问题与技术相关性，并强调研究与教育的结合。该研究计划提供了良好的机会，在使用先进的科学设备的实践经验。研究生和本科生将参与电子材料的合成，加工和表征。该项目将研究与教育推广相结合，包括（1）通过密歇根大学现有的NASA SHARP Plus计划，创建一种机制，向高中少数民族学生展示材料研究，（2）让本科生参与其中。（特别是妇女和少数民族学生）在职业生涯早期从事研究，及（3）透过互联网遥控电子显微镜，把纳米世界带到教室。计划使用该设施向高中班级演示如何在原子尺度上操纵材料，并通过虚拟显微镜基地进行演示，同时使用该系统进行演示以吸引本科生学习材料科学和工程。参与该项目的学生将有机会学习薄膜生长技术，设备制造，材料表征，并与高中学生互动。这种跨学科的教育将为学生提供特殊的机会和广泛的视角，在工业和学术研究中都有价值。

Objectives of this project are: (1) to expand basic knowledge of growth and property characterization of high-quality oxide semiconductor thin films and p-n heterostructures; (2) to systematically characterize electrical transport properties of the films and p-n heterostructures as a function of chemical doping, film thickness, bias applied, and temperature; (3) to fabricate model systems based on epitaxial single crystal films consisting of field effect transistor (FET) structures and develop a fundamental understanding of the effect of bias applied across the p-n junction on electrical transport properties and selective adsorption properties; and (4) to explore fabrication and characterization of more complex devices such as bipolar transistors with an exposed p-n junction. These devices offer the possibility of amplified electronic response to adsorption at exposed p-n junctions, which may provide a new level of control at the atomic and molecular level.The long-term goal is to develop a fundamental understanding of oxide-based semiconductor heterostructures suitable for the design of nanoengineered sorbents, tunable displays, catalytic materials, and chemical sensors. The understanding gained is expected to provide guidance for improvement of chemical selectivity and sensitivity, and provide a science base for the development of microelectronic devices for selective, tunable chemical sensing. The insights gained will be beneficial not only for advancing chemical sensor technology and for improving health and safety in society, but also impact the basic research and technology development of transparent electrodes for electronic and optical devices. Additionally, through collaboration with Ford, fundamental information that this project will provide may improve emissions control technology for lean-combustion engines. Thus, the intellectual and broader impact of the proposed research may reach well beyond the realm of chemical sensing.%%% This project addresses basic materials research issues in a topical area of materials science with technological relevance, and places emphasis on the integration of research and education. The research program provides excellent opportunities for hands-on experience in the use of sophisticated scientific equipment. Graduate and undergraduate students will be involved in the synthesis, processing, and characterization of electronic materials. The project integrates research with educational outreach which includes (1) creating a mechanism to expose materials research to high school minority students through the existing NASA SHARP Plus program at the University of Michigan, (2) involving undergraduates (particularly women and minority students) in research early in their careers, and (3) bringing the nano-world to the classroom through remote control of electron microscopes via the internet. It is planned to use this facility to demonstrate to a high school class, both live and via a virtual microscopy base, how materials can be manipulated at the atomic scale, and also to use this system for demonstrations to attract undergraduates to materials science and engineering. Students involved in this project will have the opportunity to learn film growth techniques, device fabrication, materials characterization, and to interact with high school students. This interdisciplinary education will provide students with special opportunities and a broad perspective valued in both industrial and academic research.***