Observed coexistence of memristive, memcapacitive and meminductive characteristics in polyvinyl alcohol/cadmium sulphide nanocomposites

Undoped and copper doped cadmium sulphide nanoparticles embedded in polyvinyl alcohol matrix (PVA/CdS) were synthesized by adopting chemical route. The effects of doping with Cu on the structural, optical and electrical properties of the as-prepared samples are reported. X-ray diffraction (XRD) results showed a mixed phase of cubic and hexagonal in the Cu-doped samples and only cubic phase was observed in the undoped sample. The estimated crystallite/particle size from the XRD, HRSEM and HRTEM is in the range of 2–10 nm. UV–Vis revealed blue shift of the absorption wavelength suggesting quantum confinement. Photoluminescence emission shows red shifting of emission peaks in Cu-doped PVA/CdS samples in comparison to undoped PVA/CdS. Two terminal electrochemical devices were fabricated, with the as-synthesized undoped and copper doped PVA/CdS NC samples as the active layer on ITO coated glass slide and silver (Ag) electrodes. I–V characteristics of the as-fabricated Ag/PVA/CdS NCs/ITO devices exhibit non-zero crossing hysteresis behaviour. The observed behaviour suggests co-existence of extended memristive characteristics with memcapacitive/meminductive characteristics classified as characteristic of extended memelements.