Institute of Microstructure and Properties of Advanced Materials, Beijing University of Technology , Beijing 100124, China.
Department of Materials Science and NanoEngineering, Rice University , Houston, Texas 77005, United States.
Nano Lett. 2017 Feb 8;17(2):851-855. doi: 10.1021/acs.nanolett.6b04118. Epub 2017 Jan 17.
Controlling phase transition in functional materials at nanoscale is not only of broad scientific interest but also important for practical applications in the fields of renewable energy, information storage, transducer, sensor, and so forth. As a model functional material, vanadium dioxide (VO) has its metal-insulator transition (MIT) usually at a sharp temperature around 68 °C. Here, we report a focused electron beam can directly lower down the transition temperature of a nanoarea to room temperature without prepatterning the VO. This novel process is called radiolysis-assisted MIT (R-MIT). The electron beam irradiation fabricates a unique gradual MIT zone to several times of the beam size in which the temperature-dependent phase transition is achieved in an extended temperature range. The gradual transformation zone offers to precisely control the ratio of metal/insulator phases. This direct electron writing technique can open up an opportunity to precisely engineer nanodomains of diversified electronic properties in functional material-based devices.
在纳米尺度上控制功能材料的相转变不仅具有广泛的科学意义，而且对于可再生能源、信息存储、换能器、传感器等领域的实际应用也很重要。作为一种模型功能材料，二氧化钒（VO）通常在大约 68°C 的急剧温度下发生金属-绝缘体转变（MIT）。在这里，我们报告了聚焦电子束可以直接将纳米区域的转变温度降低到室温，而无需对 VO 进行预图案化。这个新过程被称为辐照辅助 MIT（R-MIT）。电子束辐照形成了一个独特的渐变 MIT 区，其大小是光束尺寸的几倍，在这个区域中，可以在扩展的温度范围内实现温度相关的相转变。渐变的转变区可以精确控制金属/绝缘相的比例。这种直接的电子写入技术可以为在基于功能材料的器件中精确设计各种电子性能的纳米域提供机会。
