Conduction Mechanisms in Polyvinyl Alcohol: CdS/CdS:Cu Nanoparticle Hybrid Nanocomposites.

ABSTRACT

The electrical conduction mechanisms were investigated for the CdS and Cu-doped CdS (CdSCu) nanoparticles embedded in polyvinyl alcohol (PVA) (PVA/CdS and PVA/CdSCu) nanocomposites; synthesized by the chemical Sol Gel method on indium tin-oxide (ITO) substrate. X-ray diffraction pattern results show that the PVA/CdS nanocomposite is hawleyite-sturcture and PVA/CdSCu nanocomposites show greenockite-hawelyite mixed structure. The sizes of CdS and CdSCu nanoparticles were estimated from transmission electron microscopy (TEM) images and are ≈4 nm and ≈10 nm respectively; which were formed inside the PVA polymer layer. The devices were fabricated with Ag and ITO as electrodes with PVA/CdS and PVA/CdSCu nanocomposites as an active layers. The current-voltage (I-V ) relationships measurements shows the nature is extended memrisitve features for both PVA/CdS and PVA/CdSCu nanocomposites. The ION/IOFF ratios are enhanced and become more prominent in case of PVA/CdSCu nanocomposites device. The resistive switching characteristic show Schottky, Trapped-charge limited current (TCLC) and Space charge limited conduction (SCLC) mechanisms in Ag/PVA/CdS/ITO device; whereas Schottky, Ohmic, TCLC and SCLC were observed in Ag/PVA/CdSCu/ITO device.