Dielectric relaxation behavior of CdS nanoparticles and nanowires

The dielectric relaxation and scaling behavior of CdS nanoparticles and nanowires were investigated in the frequency range 10(2)-10(6) Hz and in the temperature range 373-573 K by complex impedance spectroscopy and electric modulus spectroscopy. Studies on the complex permittivity revealed that the dielectric relaxation in CdS nanostructures deviates from Debye like behavior. A detailed study on the grain and grain boundary charge transport was carried out. The charge carrier transport in CdS nanostructures was identified to be hopping of polarons. From the combined analysis of the variation of imaginary part of electric modulus and complex impedance with frequency, it was found that at high temperatures localized conduction is dominant in CdS nanoparticles where as the long range hopping process is dominant with nanowires. It was also found that the scaling behavior of CdS nanoparticles varied considerably from that reported earlier.