微纳尺度VO2的力致相变机制及力电耦合性能研究

项目名称： 微纳尺度VO2的力致相变机制及力电耦合性能研究

项目编号： No.51302207

项目类型： 青年科学基金项目

立项/批准年度： 2014

项目学科： 一般工业技术

项目作者： 陈凯

作者单位： 西安交通大学

项目金额： 25万元

中文摘要： 作为一种相变点接近室温的金属-绝缘体相变(MIT)材料，VO2有望在信息技术中取代传统材料以保持摩尔定律的有效性，因此其微纳尺度性能备受关注。研究表明其MIT可由温度或应力引发并伴随结构相变(SPT)，相变机制决定MIT与SPT是否同步。目前对MIT机制的研究集中于热致相变，而对力致相变机制的研究比较缺乏。由于VO2具有多个结构复杂的绝缘体相且这些相可在一定的应力作用下相互转变，科学界对VO2的力致相变路径仍存在争议，且对VO2器件在服役条件下的可靠性缺乏定量研究，极大限制了其应用。本项目针对力致相变机制和器件可靠性这两大问题，以一维VO2微纳单晶为研究对象，采用原位TEM与原位同步辐射相结合的技术，利用多场耦合测试平台，系统定量地研究微纳尺度VO2力致相变的路径，力致相变与SPT的时间先后顺序，及电阻率随应变的变化规律，揭示相变机制，预测VO2器件的可靠性，为实际应用提供坚实的实验基础。

中文关键词： VO2单晶纳米线；原位透射电子显微镜；同步辐射微衍射；力电耦合；金属-绝缘体相变

英文摘要： Metal-insulator transition (MIT) materials are considered to be alternate candidates for information processing to replace the Si-based technology to keep the Moore's law alive. As a MIT material, the properties of VO2 at micro to nano scale has been widely studied because its metal-insulator transition (MIT) temperature (~341 K) is experimentally easily accessible. It has been unveiled that the MIT in VO2 can be triggered by both temperature and stress and is accompabied with structural phase transition (SPT). However, the mechanism of the MIT in VO2 is still under debate due to the presence of several complex insulating phases that have similar free energies and can be controlled by fluctuation of temperature and stress. The reliability of the VO2-based devices is also lack of study. We propose to approach the full understanding of the pathway of the MIT by investigating systematically the evolution of crystal structures of VO2 micronano structures without and under various external stresses by taking advantage of the in situ multi-field coupling test stage and the high structure resolution of synchrotron polychromatic x-ray microdiffraction. By applying the in situ quantitative TEM technique, the electrical and mechanical properties coupled with the elastic deformation and phase transition of VO2 will b

英文关键词： VO2 single crystalline nanowires；in situ transmission electron microscope (TEM)；synchrotron X-ray microdiffraction；mechanoelectrical testing；metal-insulator transition (MIT)