Structural, electrical and magnetic properties of glucose-capped CdS nanoparticles

CdS nanoparticles are synthesized by a simple chemical co-precipitation technique using glucose as a capping/complexing agent and their structural, morphological, electrical and magnetic properties are studied. X-ray diffraction results reveal the pure phase formation of CdS nanoparticles along with a wurtzite structure. The interaction of the glucose with CdS nanoparticles is evident from the distinct absorption bands and peaks in the Fourier transform infrared spectra. Field effect scanning electron microscope and high resolution transmission electron microscope images depict weakly aggregated spherical nanoparticles of size ∼2–20 nm. The selective area electron diffraction pattern exhibits well-resolved diffraction rings representing the polycrystalline nature of the nanoparticles. The optical band gap has been calculated using Tauc's plot and found to be 2.58 eV, which is higher than the band gap of the bulk phase wurtzite CdS. The existence of the excitonic peak and the blue-shift in the absorption threshold confirm the quantum confinement in the synthesized nanoparticles. The temperature dependence of d. c. conductivity is studied and observed a linear response through current–voltage characteristics. Weak ferromagnetism is also observed in the synthesized CdS nanoparticles irrespective of the diamagnetic nature of CdS in bulk form. The observation of weak ferromagnetism in the synthesized nanoparticles proposes them as a potential candidate for diluted magnetic semiconductors.