Su Shubin, Li Hao, Huang Jingxian, Zhang Zhibin, Liang Chenhui, Jiang Wenxiang, Deng Aolin, Liu Kaihui, Shi Zhiwen, Qian Dong, Tao Haihua
State Key Laboratory of Advanced Optical Communication Systems and Networks, School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, China.
State Key Laboratory for Mesoscopic Physics, Collaborative Innovation Center of Quantum Matter, School of Physics, Peking University, Beijing 100871, China.
ACS Appl Mater Interfaces. 2020 Dec 9;12(49):55382-55389. doi: 10.1021/acsami.0c16005. Epub 2020 Nov 23.
Properly cutting graphene into certain high-quality micro-/nanoscale structures in a cost-effective way has a critical role. Here, we report a novel approach to pattern graphene films by HO-based magnetic-assisted ultraviolet (UV) photolysis under irradiation at 184.9 nm. By virtue of the paramagnetic characteristic, the photo-dissociated hydroxyl [OH(XΠ)] radicals are magnetized and have their oxidation capability highly enhanced through converting into an accelerated directional motion. Meanwhile, the precursor of HO(X̃A) molecules distributes uniformly thanks to its weak diamagnetic characteristic, and there exists no instable diamagnetic intermediate to cause lateral oxidation. Possessing these unique traits, the HO-based magnetic-assisted UV photolysis has the capability of making graphene microscale patterns with the linewidth down to 8.5 μm under a copper grid shadow mask. Furthermore, it is feasible to pattern graphene films into 40 nm-wide ribbons under ZnO nanowires and realize hybrid graphene/ZnO nanoribbon field-effect transistors with a hole mobility up to 7200 cm·V·s. The X-ray photoelectron spectroscopy and time-of-flight secondary ion mass spectrometry analyses reveal that OH(XΠ) radicals act as a strong oxidant and that another product of H(1S) adsorbs weakly on graphene.
以经济高效的方式将石墨烯精确切割成特定的高质量微/纳米级结构具有至关重要的作用。在此，我们报告了一种通过基于HO的磁辅助紫外（UV）光解在184.9 nm辐射下对石墨烯薄膜进行图案化的新方法。借助顺磁特性，光解离的羟基[OH(XΠ)]自由基被磁化，并通过转化为加速的定向运动使其氧化能力得到极大增强。同时，HO(X̃A)分子的前体由于其弱抗磁特性而均匀分布，并且不存在导致横向氧化的不稳定抗磁中间体。基于HO的磁辅助UV光解具有这些独特特性，能够在铜网格阴影掩膜下制作出线宽低至8.5μm的石墨烯微尺度图案。此外，在ZnO纳米线下方将石墨烯薄膜图案化为40nm宽的带，并实现空穴迁移率高达7200 cm·V·s的混合石墨烯/ZnO纳米带场效应晶体管是可行的。X射线光电子能谱和飞行时间二次离子质谱分析表明，OH(XΠ)自由基作为强氧化剂，而H(1S)的另一种产物在石墨烯上的吸附较弱。
