Study of Electronic Structure, Magnetic and Optical Properties of Sn1-xCoxO2 Semiconductors using Density Functional Theory

In this paper electronic structure, magnetic and optical properties of pure SnO2 and Sn1-xCoxO2 (x= 6.25%, 12.5%, 18.75% and 25%) samples and effect of Oxygen vacancies on those were investigated using density functional theory (DFT). Density of states and band structure curves show Co doping causes increase in energy surfaces near to the Fermi level. The results of this study showed the ground states of the 12.5% and 25% samples were ferromagnetic. The study of the effects of Oxygen vacancy on 12.5%Co doped- sample revealed that the introducing of vacancies causes increase in magnetic moment of the Co ions. The results were also showed that by increasing the Co concentration up to 12.5% the optical band gap decreases and then by more increasing of Co it increases. The intensity of the first peak in absorption curve increases and the intensity of the other peak above the 6eV decreases. The red shift of peak positions was also observed on absorption curves with increasing Co concentration to 12.5%.