Characterization of the geometrical and structural characteristics of oxidized Cu area in high resolution is crucial for tracking the change in morphology, exploring interactions between graphene layers and Cu substrates and revealing the mechanism for the orientation‐dependent oxidation of Cu. Here, we reported experimental results on nanoscale imaging of natural oxidation of the polycrystalline Cu substrate coated by partial‐coverage chemical vapor deposition (CVD)‐grown graphene stored in dryer under ambient conditions for up to 10 months. Scanning electron microscope (SEM), together with atomic force microscope (AFM), Raman, and X‐ray photoelectron spectroscopy (XPS), was used for systematically studying the morphological and compositional changes at nanoscale during oxidation. The appearance of oxidized Cu substrates could be unambiguously distinguished from the unoxidized regions based on their distinctly different morphologies in SEM images, and the underlying mechanism was discussed in detail. By analyzing a millimeter‐seized polycrystalline Cu substrate, we found that the oxidation of polycrystalline Cu substrate depends sensitively on both orientation of graphene layers and Cu substrates. Furthermore, the time‐dependent oxidation evolution of Cu substrate was also established, and the oxidation rate was readily determined. The findings reported here will have important implications for developing protection coatings for Cu.

Two-dimensional dopant profiling is vital for the modelling, design, diagnosis and performance improvement of semiconductor devices and related research and development. Scanning electron microscopy (SEM) has shown great potential for dopant profiling. In this study, the effects of secondary electron (SE) detectors and imaging parameters on the contrast imaging of multilayered p-n and p-i junction GaN specimens via SEM were studied to enable dopant profiling. The doping contrast of the image captured by the in-lens detector was superior to that of the image captured by the side-attached Everhart-Thornley detector at lower acceleration voltages (V acc ) and small working distances (WD). Furthermore, the doping contrast levels of the in-lens detector-obtained image under different combinations of V acc and WD were studied, and the underlying mechanism was explored according to local external fields and the refraction effect. The difference in the angular distributions of SEs emitted from different regions, the response of the three types of SEs to detectors, and the solid angles of detectors toward the specimen surface considerably influenced the results. This systematic study will enable the full exploitation of SEM for accurate dopant profiling, improve the analysis of the doping contrast mechanism, and further improve doping contrast for semiconductors.

Graphene oxide is an ideal nanofiller for epoxy resins because of its excellent mechanical properties, high thermal resistance, and abundant oxygen-containing functional groups. However, the poor dispersion of graphene oxide in epoxy resins restricts its application in corrosive environments. In this study, epoxy coating was prepared by incorporating triethanolamine (TEA)-modified graphene oxide (TEA-GO-EP). TEA acted as a modification agent for graphene oxide to improve its dispersion in epoxy and corrosion inhibitor for the underlying copper substrate. The long-term potentiodynamic polarization and electrochemical impedance spectroscopy results demonstrated the improved anti-corrosion performance of the TEA-GO-EP coatings in 3.5 wt.% NaCl aqueous solution, compared with the coatings without TEA. Moreover, the anti-corrosion mechanism was discussed in detail. The findings reported in this paper have important implications for developing new types of eco-friendly epoxy-based coatings.

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