Fabrication of Al deposited sandwich capacitor structure with CdSe/PVA dielectric thin film by spin coating technique for high power applications: synthesis and characterizations

The capacitor structures were fabricated in the configuration of Al : CdSe/PVA : Al with CdSe/PVA as an insulating dielectric layer for high power applications. The sandwiched layer gave an excellent energy density and a better dielectric strength that was obtained from the amalgamation of CdSe and poly (vinyl alcohol). For the detailed analysis of the interaction between CdSe and PVA, transparent CdSe/PVA composites were synthesized by ultra-sonication technique with micrometer thicknesses at different wt% of CdSe. The UV absorption edge of PVA matrix corresponds to π→π* transition associated with ethylene unsaturation (C=C) was analysed and it was shifted towards higher wavelength with the CdSe incorporation. The sub-band states formation was evaluated, Urbach energy was increased up to ~835 meV, and an increase in structural defect was noticed by widening the tail state within the polymer matrix with the impurity addition. Optical parameters which include extinction coefficient (k) and index of refraction (n) have been determined. Three dielectric relaxations were pronounced as α, β and interfacial polarization and the high relative permittivity and the low values of dissipation factor indicated that the dielectric phenomenon was predominant in all membranes. Inspection of electrical conduction rate to temperatures was also investigated and the temperature coefficient of capacitance and temperature coefficient of permittivity were listed. Thermal stability could be enhanced with CdSe interaction and the variation in thermal parameters was discussed.