Effect of ITO Nanoparticles on Dielectric Relaxation Processes and an Analysis of The Electric Impedance Characteristics of ITO/Epoxy Nanocomposites for Embedded Capacitor Devices
Epoxy/ITO nanocomposites containing various filler ITO concentrations by weight were successfully fabricated. Using Differential Scanning Calorimetry (DSC), a thermo-analytical technique used to study the glass transition temperatures, we expected to find a restriction in the molecular mobility of the polymer chains that might confirm the influence of incorporating ITO contents into the epoxy material. Several complementary techniques were investigated, such as dielectric relaxation spectroscopy (DRS) at the range of frequency (10−1–106) Hz and over the temperature range from − 80°C to 240°C, and time-domain spectroscopy (TDS) with frequency domain (10−5–10−1) Hz. The experimental data were investigated and interpreted in terms of various dielectric formalisms. For TDS results, the neat epoxy is affected by the added ITO nanoparticles. In the low-frequency domain of TDS measurements, the depolarization current curves of the nanocomposites are precisely fitted in a parallel circuit (RiCi) association model. The obtained dielectric data of TDS analysis shows two interfacial relaxation processes. The first wide peak was mainly ascribed to the charge accumulations ITO-polymer interfaces and the additional peak can be related to the charge accumulated at the interface material-electrodes. Impedance evaluated data were analyzed using a consistent electrical circuit formalism. From − 80°C to 60°C, the nanocomposites exhibited an ohmic behaviour within the added ITO nanofiller. Between 60°C and 120°C, the nanocomposites exhibit a capacitive contribution behavior which makes the material suitable for capacitors devices. Above 120°C, the Nyquist design illustrations [(− Z″) versus (Z′)] are well theoretical fitted to an equivalent circuit model achieved by impedance with designed parameters: resistance (Rb) and constant phase element (CPE) combinations.