The Doping Effect on the Electronic Properties of the Titanium Dioxide TiO2: A DFT Study

In this work, we study the electronic and magnetic properties of the TiO2 material doped by the some elements, such as Sulfur (S), Fluorine (F), Hydrogen (H), Nitrogen (N), Potassium (K), Boron (B), Iodine (I) and Carbon (C). We have used the ab-initio method on the basis of the Density Functional Theory (DFT) using the Quantum Espresso code. Our calculations show three behaviors: semiconductor, half metallicity and full metallic. In fact, a first step, our results confirm the semi-conductor character of the pure TiO2 with a direct band gap of about 1.7 eV at the Gamma point. In the partial density of states, the O-2p orbital is found to be dominant in the valence band of the total DOS. While, the Ti-3d orbital is overriding in the conduction band of the total DOS of TiO2 material. When doping the TiO2 with Fluorine (F), we found that the band structure of the doped TiO2 material exhibits an indirect gap between M and Gamma points. On the second step, the main character of TiO2 doped with F, H and N is a half metallic behavior. Finally, when doping with the (K), (B), (I) or (C) elements, we found a full metallic behavior of this material. It is worth to note that the doping TiO2 material with Boron (B) and Iodine (I) makes appear a low magnetic character, while a more important magnetic behavior appear when doping the TiO2 with Carbon. It is found that the fact of doping TiO2 is to make it less stable.