Effect of V and Y doping on the structural, optical and electronic properties of CdS (hexagonal and cubic phases)

Nano Cd1-xYxS and Cd1-xVxS (0x0.2) systems were synthesized by a thermolysis method. X-ray phase analysis indicated the presence of two phases, cubic and hexagonal structures, for some samples. The effect of doping on the cell parameters, Cd-tetrahedron dimension, crystallite size and the mixed phases' percentages in the sample were examined applying X-ray Rietveld method. The energy gap of Y- or V-doped CdS was determined by ultraviolet spectroscopy technique. It is found out that the energy gap of V-doped CdS is less than the corresponding Y-doped CdS samples. Density function calculation (DFT) was used to confirm the decreasing in energy gap upon doping, and also to study the changes in absorption and dielectric properties of doped and undoped CdS samples in both cubic and hexagonal phases. The photoluminescence measurements revealed the presence of extra sub emissions spectra (yellow and green) upon doping CdS with Y or V compared with undoped CdS sample.