Ramadan Sami, Zhang Yuanzhou, Tsang Deana Kwong Hong, Shaforost Olena, Xu Lizhou, Bower Ryan, Dunlop Iain E, Petrov Peter K, Klein Norbert
Department of Materials, Imperial College London, London SW7 2AZ, U.K.
ACS Omega. 2021 Feb 9;6(7):4767-4775. doi: 10.1021/acsomega.0c05631. eCollection 2021 Feb 23.
The performance of graphene devices is often limited by defects and impurities induced during device fabrication. Polymer residue left on the surface of graphene after photoresist processing can increase electron scattering and hinder electron transport. Furthermore, exposing graphene to plasma-based processing such as sputtering of metallization layers can increase the defect density in graphene and alter the device performance. Therefore, the preservation of the high-quality surface of graphene during thin-film deposition and device manufacturing is essential for many electronic applications. Here, we show that the use of self-assembled monolayers (SAMs) of hexamethyldisilazane (HMDS) as a buffer layer during the device fabrication of graphene can significantly reduce damage, improve the quality of graphene, and enhance device performance. The role of HMDS has been systematically investigated using surface analysis techniques and electrical measurements. The benefits of HMDS treatment include a significant reduction in defect density compared with as-treated graphene and more than a 2-fold reduction of contact resistance. This surface treatment is simple and offers a practical route for improving graphene device interfaces, which is important for the integration of graphene into functional devices such as electronics and sensor devices.
石墨烯器件的性能常常受到器件制造过程中产生的缺陷和杂质的限制。光刻胶处理后残留在石墨烯表面的聚合物残余物会增加电子散射并阻碍电子传输。此外，将石墨烯暴露于基于等离子体的处理过程中，如金属化层的溅射，会增加石墨烯中的缺陷密度并改变器件性能。因此，在薄膜沉积和器件制造过程中保持石墨烯高质量的表面对于许多电子应用至关重要。在此，我们表明，在石墨烯器件制造过程中使用六甲基二硅氮烷（HMDS）的自组装单分子层（SAMs）作为缓冲层，可以显著减少损伤、提高石墨烯的质量并增强器件性能。已使用表面分析技术和电学测量对HMDS的作用进行了系统研究。HMDS处理的好处包括与处理后的石墨烯相比，缺陷密度显著降低，接触电阻降低超过两倍。这种表面处理方法简单，为改善石墨烯器件界面提供了一条实用途径，这对于将石墨烯集成到电子和传感器设备等功能器件中非常重要。
