Impact of Cobalt-Doping on the Optical, Magnetic, and Electronic Features of Hexagonal Cadmium Sulfide

Abstract CdS and Cd0.9Co0.1S samples were prepared under an N2 atmosphere. The structural analysis was conducted using X-ray diffraction. The structural and microstructure parameters were determined using Rietveld refinement method. The incorporation of cobalt ions into CdS matrix was confirmed by energy-dispersive spectroscopy and Fourier-transform infrared analysis. CdS sample has a non-magnetic feature while the Co-doped sample exhibited a magnetic behavior. The origin of magnetic property transformation has been investigated, revealing the emergence of ferromagnetic ordering and the conversion to a diluted magnetic semiconductor (DMS) with a calculated magnetic moment of 2.56 μB upon Co doping. We also investigated how this Cobalt-doping-driven transformation affected optical, photoluminescence, and electronic properties. These effects correlated with the emergence of hyper-deep defect states. Electronic properties were calculated using density functional theory (DFT) with the HSE06 hybrid functional approximation. The calculated energy bandgaps for both Co-doped and pure CdS were 2.13 and 2.12 eV, respectively, while experimental measurements from our UV analysis yielded values of 2.26 and 2.15 eV. DFT calculations were employed to explore the magnetic properties, absorption coefficients, refractive indices, real and imaginary dielectric components, and energy loss spectra in both samples.