Melios Christos, Huang Nathaniel, Callegaro Luca, Centeno Alba, Cultrera Alessandro, Cordon Alvaro, Panchal Vishal, Arnedo Israel, Redo-Sanchez Albert, Etayo David, Fernandez Montserrat, Lopez Alex, Rozhko Sergiy, Txoperena Oihana, Zurutuza Amaia, Kazakova Olga
National Physical Laboratory, Teddington, TW11 0LW, United Kingdom.
Department of Electrical and Computer Engineering, Faculty of Engineering, University of Cyprus, 1687, Nicosia, Cyprus.
Sci Rep. 2020 Feb 21;10(1):3223. doi: 10.1038/s41598-020-59851-1.
Graphene has become the focus of extensive research efforts and it can now be produced in wafer-scale. For the development of next generation graphene-based electronic components, electrical characterization of graphene is imperative and requires the measurement of work function, sheet resistance, carrier concentration and mobility in both macro-, micro- and nano-scale. Moreover, commercial applications of graphene require fast and large-area mapping of electrical properties, rather than obtaining a single point value, which should be ideally achieved by a contactless measurement technique. We demonstrate a comprehensive methodology for measurements of the electrical properties of graphene that ranges from nano- to macro- scales, while balancing the acquisition time and maintaining the robust quality control and reproducibility between contact and contactless methods. The electrical characterisation is achieved by using a combination of techniques, including magneto-transport in the van der Pauw geometry, THz time-domain spectroscopy mapping and calibrated Kelvin probe force microscopy. The results exhibit excellent agreement between the different techniques. Moreover, we highlight the need for standardized electrical measurements in highly controlled environmental conditions and the application of appropriate weighting functions.
石墨烯已成为广泛研究的焦点，目前它能够以晶圆规模生产。对于下一代基于石墨烯的电子元件的开发而言，石墨烯的电学特性表征至关重要，并且需要在宏观、微观和纳米尺度上测量功函数、薄层电阻、载流子浓度和迁移率。此外，石墨烯的商业应用需要对电学性质进行快速大面积测绘，而不是获取单点值，这理想情况下应通过非接触测量技术来实现。我们展示了一种全面的方法，用于测量从纳米到宏观尺度的石墨烯电学性质，同时平衡采集时间，并在接触式和非接触式方法之间保持强大的质量控制和可重复性。电学特性表征是通过多种技术的组合来实现的，包括范德堡几何结构中的磁输运、太赫兹时域光谱测绘以及校准的开尔文探针力显微镜。不同技术之间的结果显示出极佳的一致性。此外，我们强调了在高度受控的环境条件下进行标准化电学测量以及应用适当加权函数的必要性。
