To present more details in terms of

To present more details in terms of intergranular nanostructure of MLV device and the polymer distribution at the interface between ZnO grains, TEM (transmission electron microscopy) and STEM-EDS (Scanning Transmission Electron Microscopy – Energy Dispersive Spectroscopy) were performed. Figure 4 shows TEM and STEM-EDS images of both ceramic-polymer/metal and ceramic/polymer interfaces in the cold sintered MLV device. Figure 4a represents a multilayer body and the rectangular frames show different spots of the multilayer device where is being examined by TEM. STEM-EDS images (Figure 4b,c) confirm that a clean interface of Cu/ZnO-PEI is obtained at a nanoscale and that the interdiffusion between Cu-metal and ZnO/PEI does not occur, as opposed to the device is fabricated at 220 °C (Figure S1 in the Supporting Information) where interdiffusion may occur (Figure S2b and S2c in the Supporting Information).