Analog Memristive and Memcapacitive Characteristics of Pt-Fe2O3 Core-Shell Nanoparticles Assembly on p+-Si Substrate

Analog memristive and memcapacitive switching characteristics were investigated in Pt-Fe2O3 core-shell nanoparticles (NPs) assembly on p(+)-Si substrate. The Ti/NPs/p(+)-Si structure exhibited gradually changing resistance (memristive) and capacitance (memcapacitive) at the same time as repeating the application of voltage with respect to the polarity of voltage. As applying negative voltage at top Ti electrode, the resistance decreased and the capacitance increased due to the increase of diffusion capacitance at n-NPs/p(+)-Si junction. On the other hand, applying the positive voltage increased resistance and decreased capacitance by increasing depletion width at the junction. The polarity-dependent resistance and capacitance changes are thought to be ascribed to the charging of the NPs assembly that alters the potential of the assembly. The concurrent analog memristive and memcapacitive characteristics also emulated the biological synaptic potentiation and depression motions, which is indicative of potential application to neuromorphic devices as well as analog nonvolatile memory and circuits.