Characterization of 2D Jammed Granular Memristive Copper Arrays

A novel sensor made of jammed granular memristive copper spheres was explored in an effort to develop a protection technology that could be used in non-proliferation treaty monitoring. The micro-copper spheres were annealed for various times at a constant temperature. SEM, EDS, and XPS were used to characterize the growth of the oxide coating. Electrical characterization of the device was done by confining the granular copper spheres to a two-dimensional plane using a unique test fixture capable of measuring I-V curves at the boundary of the circuit board using tungsten pillar electrodes. Electroforming of the copper spheres produced soft dielectric breakdown in the oxide layer, creating conductive filaments. It was shown that the conductivity of the filaments increased by reduction of the copper oxide using a field-driven process. Similarly, the conductivity of the filament decreased via oxidation assisted by Joule heating. The affects of mechanical force on the conductive filaments were also studied. The changes in the electrical resistance can be used as a detection and sensing mechanism for electromechanical interferences