Transport characteristics and colossal dielectric response of cadmium sulfide nanoparticles

We report here the synthesis of similar to 20nm sized cadmium sulfide (CdS) nanoparticles via conventional solid state reaction at low temperature similar to 200 degrees C and ambient pressure. X-ray diffraction and high resolution transmission electron microscopy analysis confirmed the synthesis of hexagonal phased nanoparticles. Impedance and electrical modulus investigations were carried out in the frequency range 20 Hz to 2 MHz and at temperature from 300 K to 400 K, which show the presence of bulk, grain boundary, and sub-grain boundary phases in CdS nanoparticles. Overlapped large polaron tunneling was the observed mechanism of charge carriers in used temperature range. The presence of colossal dielectric constant in the system is attributed to the Maxwell-Wagner type polarization. High and temperature dependent dielectric constants make the CdS nanoparticles efficient material to be used in capacitive energy storage devices. (C) 2013 AIP Publishing LLC.