电场激励条件下VO2薄膜非均匀相变的演化机制及相变速度调控研究

VO2的超快半导体-金属相转变速度是其在高速光电器件中应用的基础。针对目前VO2薄膜的相变速度快慢不一，尤其是电致相变速度过慢的问题，提出研究外加电场条件下VO2薄膜在微观尺度上的非均匀相变现象，并计划通过改善薄膜的相变均匀性，提高其相变速度。本项目将研究电场激励条件下VO2的非均匀相变形成和演化机制，以及这种相变非均匀性与薄膜相变速度的关联性；系统分析微观结构、化学组成（+4价钒氧化物比例、元素单一掺杂或复合掺杂条件）和内应力等对薄膜相变均匀性的影响规律，并在此基础上，通过对VO2薄膜微观结构参数、组成和内应力状态的可控调整和综合优化设计，改善其相变均匀性，从而提高薄膜的相变速度，进而为VO2薄膜在THz波开关、调制、存储等功能器件领域的应用提供基础，促进其发展。

The ultrafast semiconductor-metal phase transition of vanadium dioxide (VO2) is the foundation for its application in high-speed optoelectronic devices. In order to improve the transition speed of electric field triggered phase transition in VO2 film, we propose to study the inhomogeneous phase transition phenomenon in the VO2 film triggered by electric field, and then improve this inhomogeneous for achieving faster phase transition speed in the film. We will investigate the formation and evolution mechanism of the inhomogeneous phase transition induced by electric field, as well as the correlation between this inhomogeneous phase transition and the transition speed. Then we will prepare the VO2 films with different microstructure, stoichiometry (the ratio of +4 valence vanadium in the film, single doping or multiple doping) and internal stress, and elucidate their effects on the inhomogeneous phase transition in the film. Moreover, we will regulate and optimize these factors, aimed at realizing much faster transition speed in the VO2 film. Our research may provide significant insights for the application of VO2 film in ultrafast terahertz devices, such as switching, modulation and memory.