Droplet-Confined Electroplating for Nanoscale Additive Manufacturing: Current Control of the Initial Stages of Growth of Copper Nanowires.

Droplet-confined electrodeposition enables a precise deposition of three-dimensional, nanoscopic, and high purity metal structures. It aspires to fabricate intricate microelectronic devices, metamaterials, plasmonic structures, and functionalized surfaces. Yet, a major handicap of droplet-confined electrodeposition is the current lack of control over the process, which is owed to its dynamic nature and the nanoscopic size of the involved droplets. The deposition current offers itself as an obvious and real-time window into the deposition and needs to be analyzed operando. Nucleation and growth dynamics are evaluated systematically. Our results indicate different deposition regimes and link the current to both morphology and volume of deposited copper. This allows for optimized electroplating strategies and calibration of the slicing algorithms necessary for a controlled deposition of 3D structures with different solvents. The potential of selecting appropriate solvents further readies this novel technique for the reliable deposition of functional structures with submicron resolution.