Application Of The Quantum Espresso Code To Study The Structural And Electronic Properties Of Titanium Dioxide: A DFT Study

Abstract

Titanium dioxide attracts great attention as a wide band gap transition metal oxide due to its n-type semiconducting property which makes it to have many applications in industry, an area that has not been fully investigated. This study therefore focuses on the investigation of the structural properties and electronic band structures of the two phases of TiO2, the rutile and anatase using ab-initio methods. The structural properties were obtained using generalized gradient approximation (GGA) employing pseudo-potentials and plane wave basis sets. For the two TiO2 phases the calculated equilibrium lattice constants, bulk moduli and bond lengths were found to agree with a number of other recent theoretical calculations and also with experimental findings. The electronic properties were also investigated. Perfect bulk rutile and anatase gave band gaps of 2:09 eV and 2:48 eV respectively under ground state conditions. Valence band width (VB) of 1:65 eV and conduction band with (CB) of 5:917 eV were observed for rutile, TiO2 while V B of 3:98 eV and CB of 2:05 eV were observed for anatase TiO2 all in agreement with experimental values.