Feng Panpan, Zhang Dan, Zhang Peng, Wang You, Gan Yang
School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin 150001, P. R. China.
MIIT Key Laboratory of Critical Materials Technology for New Energy Conversion and Storage, School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin 150001, P. R. China.
Phys Chem Chem Phys. 2023 Mar 22;25(12):8816-8825. doi: 10.1039/d2cp05809j.
Characterization of the interfacial oxidation layer of graphene/metal is a challenging task using conventional spectroscopy techniques because interfacial oxidation is heterogeneous at the nanoscale underneath the graphene. Here we developed a feasible method for nanoscale characterization of the interfacial oxidation layer of graphene/Cu (Gr/Cu) based on scanning electron microscopy (SEM) electron beam irradiation (EBI) induced reduction of interfacial oxides (SEM EBI-RIO method) at room temperature. The change in the thickness and coverage of the interfacial Cu oxide layer induced by EBI is responsible for the observed contrast reversal or change in SEM images of a targeted area with a width down to 200 nm in the EBI time scale of seconds to minutes. This method offers the capability of mapping heterogeneous interfacial oxidation of Gr/Cu with sub-100 nm spatial resolution and determining the range of thickness (1-5 nm) of the interfacial oxide layer. The SEM EBI-RIO method will be a powerful method to complement X-ray photoelectron spectroscopy (XPS), Raman microscopy, and high resolution transmission electron microscopy (HRTEM) for characterization of the interfacial oxidation layer of 2D materials and devices.
使用传统光谱技术表征石墨烯/金属的界面氧化层是一项具有挑战性的任务，因为在石墨烯下方的纳米尺度上，界面氧化是不均匀的。在此，我们基于扫描电子显微镜（SEM）电子束辐照（EBI）诱导的室温下界面氧化物还原，开发了一种用于纳米尺度表征石墨烯/Cu（Gr/Cu）界面氧化层的可行方法（SEM EBI-RIO方法）。EBI引起的界面Cu氧化物层厚度和覆盖率的变化，导致在秒到分钟的EBI时间尺度下，目标区域宽度低至200 nm的SEM图像中出现对比度反转或变化。该方法能够以亚100 nm的空间分辨率绘制Gr/Cu的不均匀界面氧化图，并确定界面氧化层的厚度范围（1-5 nm）。SEM EBI-RIO方法将成为一种强大的方法，可补充X射线光电子能谱（XPS）、拉曼显微镜和高分辨率透射电子显微镜（HRTEM），用于表征二维材料和器件的界面氧化层。
