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We report the effects of Ti doping on the dielectric properties of HfO2 [Hf1-xTixO2 (x = 0.2-0.8)] 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. [ABSTRACT FROM AUTHOR]

A novel approach for synthesizing stable CdSe nanoparticles is presented in this work. X-ray diffraction (XRD) analysis confirms the hexagonal crystal structure of the derived CdSe samples. The measured particle size using scanning electron microscopy (SEM) is acquiescent to the size calculated by XRD analysis. The high resolution transmission electron microscopy (HRTEM) of these nanoparticles shows the hexagonal lattice structure at higher magnification. Photoluminescence (PL) spectrum shows an intense green emission peak from the CdSe nanoparticles. The observed UV-Vis absorption peak at 361 nm shows a blue shifting of the absorption wavelength in comparison to bulk CdSe. [ABSTRACT FROM AUTHOR]