Figure -G shows the topographical images of the printed Ag electrodes at the Ag/p-Si interface. At the sintering time of 5 min (Figure ), the surface was observed to be wavy, this indicates that the removal of solvents and organics in AgInk followed by the aggregation of AgNPs formed 1-2 m size of aggregates. At the sintering time of 10 min (Figure ), 100-200 nm size of pores were observed, which can be attributed to heat shrinkage of the aggregated AgNPs. Subsequently, as the melting and aggregating of AgNPs proceed throughout the overall sample, the surface becomes to be smooth. The morphological change of the surface is observed to be diminished in the sintering time of 15 min (Figure ). The surface averaged roughness of each images is calculated and summarized in Table . The numerical aspect also indicates that the surface of the Ag electrodes at the Ag/p-Si interface becomes smooth with the sintering time. These morphological change with the sintering time are good accordance with the results of SEM observations (vide supra). Though the surface were observed to be almost flat from the topographic image in the sintering time of 30 min, the surface roughness value (3.8 nm) did not decrease to the value of the vacuum-deposited electrode (2.8 nm), which implies that some AgNPs exist in the surface and are involved in electrical contact at the interface.