Nonvolatile memory devices based on ZnO/polyimide nanocomposite sandwiched between two C60 layers

The memory effects of a three-layer nonvolatile memory device Al/C60/ZnO nanoparticles embedded in a polyimide (PI) layer/C60/p-Si were investigated by using capacitance-voltage (C-V) measurements. Transmission electron microscopy and selected area electron diffraction pattern measurements showed that ZnO nanocrystals were formed inside the PI layer. The insertion of C60 layer improved the charge trap state density in the ZnO nanoparticle. The density was estimated by the flatband voltage shift in the C-V hysteresis, which increases with the max sweep voltage. Possible operating mechanisms corresponding to the charging and discharging process in the structure are proposed on the basis of the C-V results.