The novel optical properties of CdS caused by concentration of impurity Co

Several novel optical properties of CdS doped with Co are explored using first principle calculations based on the density functional theory with Hubbard U on-site correction. The role of Co concentration on the dielectric function, optical conductivity, absorption coefficient, reflectivity and transmissivity, and complex refractive index are investigated. We suggest a concentration-regulating mechanism of isoelectronic dopant for optical properties and band gap of CdS. The mechanism is examined with the electronic structure. The results shows that CdS doped with Co at the concentration of 7.26 wt.% will become a very useful optical materials for photovoltaic cell, light-operated switch, fiber optic communication.