Investigation of Optical Characteristics and Synthesis of Cobalt-Doped Cds (Cds: Co) Using Simple and Rapid Microwave Activated Method

Abstract

Cobalt-doped cadmium sulphide semiconductor nanoparticles (CdS: Co NPs) were made using a microwave-assisted method with different cobalt concentrations. Chemicals like sodium sulphide, cobalt chloride, and cadmium acetate were used. The Debye-Scherer equation helped find the nanoparticles' size, revealing a 2 to 4 nm range. X-ray diffraction showed a zinc-blend structure. The optical bandgap energies were found to be undoped and doped are 2.44eV and 2.58eV, respectively. For pure CdS, the XRD spectra display three main peaks at 2θ = 26.68°, 44.16°, and 52.32°. Modest alterations have been noted in 2θ for Co doping levels of 3% in CdS NPs. The peaks point to the samples' cubic structure and correlate to the (1 1 1), (2 2 0), and (3 1 1) planes. The sizes of the nanoparticles, which are 2.29 nm, 3.64 nm, for pure and Co (3%) doped CdS, were determined using the FWHM and Debye Scherer equation. The substitution of Co2+ion for Cd2+ion may be the cause of the decrease in nanoparticle size observed in the Co-doped CdS sample as concentration rises. The difference in the ionic radii of Cd2+ (0.98 Å) and Co2+ (0.72 Å) shows that when the concentration of Co-doped CdS increases, the lattice constant falls.  The peak at 3646 cm-1 in the higher energy area of the 400–4000 cm–1 FTIR spectra is attributed to the O–H stretching of absorbed water on the surface of CdS. Its bending vibration confirms the existence of water. Using HRTEM, the size of the produced nanoparticles was examined. Additionally, it confirms the sample's nanocrystalline structure. For 3% Co-doped CdS, the average size of randomly chosen nanoparticles is determined.