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

Abstract

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 Γ 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 Γ 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.

Keywords:

• Titanium dioxide
• TiO₂
• doping
• electronic properties
• spin polarization
• DFT method