ZnS nanoparticles: role of Ga3+ ions substitution on the structural, morphological, optical, and dielectric properties

Due to their dynamic features, nanoparticles of semiconductor materials have been created rapidly in the past few decades and are being investigated for potential uses in a variety of disciplines. The present study focuses on the substitution of Ga3+ ions in ZnS nanoparticles to modify their structural, morphological, compositional, optical, and dielectric properties. The Ga-doped (ZnS:Ga) nanoparticles for various Ga3+ ions concentrations (i.e., 0%, 2%, 4%, 6%, 8%, 10% & 12%) are synthesized using direct co-precipitation technique and utilizing precursor solutions of Zn(CH3COO)(2), Na2S and Ga-2(SO4)(3) along with EDTA as a stabilizing agent. The structural analysis reveals that the synthesized nanoparticles exhibit a cubic crystal structure with high crystallinity and preferred (111) orientation. Fluctuations in different structural parameters have been noticed without any alteration in crystal structure after the substitution of Ga ions in ZnS matrix. The surface morphology exposes spherical-shaped ZnS:Ga nanoparticles whose compactness varies with doping concentrations. FT-IR and EDS spectra of the nanoparticles identify the presence of different functional groups and elements in the expected compositions. A blueshift in the absorption edge has been observed for all the concentrations of ZnS:Ga w.r.t. pristine ZnS indicating quantum confinement in the synthesized nanoparticles which further results in the broadening of optical bandgap in comparison to bulk value for ZnS. The room temperature dielectric measurements for ZnS:Ga nanoparticles show a high dielectric constant value up to doping level 8% beyond which it decreased. The ac conductivity values in this study varied from 10(-4) omega(-1)m(-1) for pristine to 9.66 x 10(-3) omega(-1)m(-1) for ZnS:Ga 12%.