Study of electric conduction mechanisms, dielectric relaxation behaviour and density of states in zinc sulphide nanoparticles

Abstract

Zinc Sulfide (ZnS) nanoparticles were synthesized by solid-state reaction method at 190°C. Dielectric, electrical properties, and conduction mechanism of ZnS nanoparticles were investigated. Average crystallite size and interplanar spacing of ZnS nanoparticles were approximately 4.47 nm and 1.92 Å respectively. The nanoparticles were spherical with size range of 10–20 nm. Complex impedance spectroscopy (CIS) of ZnS nanoparticles was performed at 20 Hz to 2 MHz and 236–320 K. The ZnS nanoparticles have negative temperature coefficient of resistance (NTCR). The AC measurements of ZnS nanoparticles from 236 K to 320 K revealed that the conduction in ZnS nanoparticles is due to correlated barrier hopping (CBH). The density of states (DOS) of ZnS nanoparticles have been calculated by CBH model as a function of temperature using photon frequency (fo) 1013 Hz and localized wave function (α) 1010 m−1 which ratified hopping as dominant conduction mechanism in ZnS nanoparticles.