Characterization of the intrinsic electrical properties of Nanoporous Graphene (NPG) requires transferring it from gold, its growth substrate, onto a non-conductive substrate. Once wet (i.e. chemical) transfer methods have proven unfit because of the physicochemical changes caused to NPG, the dry (i.e. physical) transfer approach arises as the most reliable method to keep NPG pristine properties. Yet, this process requires the previous electrical and chemical decoupling of NPG from gold, which is foreseen through the intercalation and post-oxidation of Cu or Al.
The present work features our results regarding Cu intercalation of NPG and post-oxidation of Cu-intercalated NPG, being the most unexpected result the spontaneous Cu intercalation of NPG at room temperature, without the need to subject the sample to any post-annealing. This shows how low the energetic barrier for its intercalation is, in the case of NPG/Au(111).
Post-oxidation of a 1.9- Cu – ML intercalated NPG sample in 1 x 10-6 mbar of oxygen while held at 200oC apparently proved successful. Copper oxide was spotted by means of visual comparison with previously reported studies of oxidation of ultrathin Cu layers on Au(111), and identification of the corresponding topographical features. Further characterization is needed in order to elucidate the oxide phase. It is remarkable that no copper oxide was found intercalating NPG. Thus, NPG may work as an oxidation protective barrier for the underneath, already intercalated copper.
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