Duan Tianbo, Li Hu, Papadakis Raffaello, Leifer Klaus
Shandong Technology Centre of Nanodevices and Integration, School of Microelectronics, Shandong University, 250101 Jinan, People's Republic of China.
Department of Materials Science and Engineering, Ångström Laboratory, Uppsala University, SE-75121 Uppsala, Sweden.
Nanotechnology. 2022 Sep 19;33(49). doi: 10.1088/1361-6528/ac8d9b.
Polymer-assisted wet transfer of chemical vapor deposited (CVD) graphene has achieved great success towards the true potential for large-scale electronic applications, while the lack of an efficient polymer removal method has been regarded as a crucial factor for realizing high carrier mobility in graphene devices. Hereby, we report an efficient and facile method to clean polymer residues on graphene surface by merely employing solvent mixture of isopropanol (IPA) and water (HO). Raman spectroscopy shows an intact crystal structure of graphene after treatment, and the x-ray photoelectron spectroscopy indicates a significant decrease in the C-O and C=O bond signals, which is mainly attributed to the removal of polymer residues and further confirmed by subsequent atomic force microscopy analysis. More importantly, our gated measurements demonstrate that the proposed approach has resulted in a 3-fold increase of the carrier mobility in CVD graphene with the electron mobility close to 10 000 cmVS, corresponding to an electron mean free path beyond 100 nm. This intrigues the promising application for this novel method in achieving ballistic transport for CVD graphene devices.
聚合物辅助的化学气相沉积（CVD）石墨烯湿法转移在实现大规模电子应用的真正潜力方面取得了巨大成功，而缺乏有效的聚合物去除方法被认为是实现石墨烯器件高载流子迁移率的关键因素。在此，我们报告了一种高效且简便的方法，仅使用异丙醇（IPA）和水（HO）的混合溶剂就能清洁石墨烯表面的聚合物残留物。拉曼光谱显示处理后石墨烯的晶体结构完整，X射线光电子能谱表明C-O和C=O键信号显著降低，这主要归因于聚合物残留物的去除，并通过随后的原子力显微镜分析得到进一步证实。更重要的是，我们的门控测量表明，所提出的方法使CVD石墨烯中的载流子迁移率提高了3倍，电子迁移率接近10000 cmVS，对应电子平均自由程超过100 nm。这激发了这种新方法在实现CVD石墨烯器件弹道输运方面的广阔应用前景。
