Effects of Ti Doping on the Dielectric Properties of HfO2 Nanoparticles

We report the effects of Ti doping on the dielectric properties of HfO2 [Hf1-xTixO2 (x = 0.2-0.8)1 nanoparticles at room temperature. The Hf1-xTixO2 nanoparticles were synthesized by a wet chemical process. The structural and morphological properties of the derived samples were analyzed with X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and high resolution transmission electron microscopy (HRTEM). Impedance analysis was performed in pelletized samples in the frequency range of 1 MHz to 1 GHz. The obtained results were analyzed in correlation with microstructure and doping concentration in the derived samples. The average size of the Hf1-xTixO2 nanoparticles is typically in the range of 4-8 nm depending on the processing temperature. The Hf1-xTixO2 nanoparticles show reduction in crystallinity with the increase in Ti doping. The dielectric constants of the derived samples decrease with the increase in frequency. The ac-conductivity in the samples increases with the increase in frequency irrespective of Ti concentration and shows significant drop with the increase in Ti concentration at all frequencies.