Solid State Electrochemical Direct Writing of Copper Nanostructures on an Ion Conductive Phosphate Glass Using Atomic Force Microscopy

In this paper, we report a solid state direct writing method for fabricating copper nanostructures in seconds using atomic force microscopy. Under ambient conditions, a dendritic electrochemical reaction on the surface of a super-ionic (CuI)_x (CuPO₃)_{(1- x)} glass surface is demonstrated by negatively biasing an atomic force microscopy (AFM) probe relative to a Cu film counter electrode. Energy dispersive X-ray spectroscopy (EDS) is then used to characterize the dendrite and confirm electrochemical extraction of copper on the glass surface. To implement controlled electrochemical extraction, the copper growth process is then localized by realizing a ∼pA level current controlled electrochemical extraction process with a stationary AFM tip. Line patterns with ∼200 nm line-width are then generated in seconds over areas tens of microns in diameter by moving the AFM tip along the desired pattern while supplying a constant current to the tip. To the best of our knowledge, this is the first demonstration of a solid state direct writing approach for making copper nano-patterns on an ion conductive glass substrate.