Fabrication of quantum effective and polymer controlled functional metal oxide dielectric materials and investigation of their electro-optical properties

In this thesis study, undoped and PANI-doped ZnO-CdO composite materials were synthesized using the hydrothermal method. The synthesized composite materials were investigated according to their doping ratios. The synthesis was carried out at 180 degrees Celsius for a duration of 24 hours, depending on the additive concentration. The structural, optical, dielectric properties, and chemical compositions of the synthesized composite materials were examined. The structural, chemical, and dielectric properties of the materials were analyzed using scanning electron microscopy (SEM), Fourier-transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), UV-Vis spectrophotometry, and impedance spectroscopy, respectively. FT-IR analyses confirmed the realization of doping through variations in the intensities of the vibrational peaks, while in undoped samples, different thermal treatments also affected the peak intensities. XRD analysis showed that both thermal treatment and doping led to changes in peak intensity and amplitude, which in turn influenced the crystallite size of the materials. The capacitance, impedance, conductivity, and dielectric properties of the PANI-doped ZnO-CdO capacitors were investigated in the frequency range of 1 kHz to 10 MHz. The semicircular shapes observed in the Reactance (X)–Series Resistance (Rs) plots of the PANI-doped ZnO-CdO capacitors, as well as in the Conductance (G)–Susceptance (B) graphs of the undoped and PANI-doped CdO materials, indicate that these composite materials exhibit dielectric polarization in response to external stimuli. It was observed that the dielectric properties of the materials changed depending on the amount of PANI doping. In conclusion, the capacitance, impedance, and dielectric properties obtained in this thesis study suggest that ZnO-CdO/PANI structures have potential for use as sensor materials.