Electronic Structure of Vanadium-Doped TiO2 of Both Anatase and Rutile Based on Density Functional Theory (DFT) Approach

Abstract

Study of the theoretical  approah to calculate the band structure and density of states (DOS) of vanadium-doped TiO 2 of both anatase and rutile have been done. The first-principle calculations were done using supercell (2x1x1) method. The first-principle calculation of V-doped TiO 2 of both anatase and rutile were analyzed by density-functional theory (DFT) with generalized gradient approximation from Perdew-Burke-Ernzerhof (GGA+PBE), Perdew-Wang’s 1991 (GGA+PW91) and local density approximation (LDA) for exchange-correlation functionals. The calculation of electronic structures show that the V-doped TiO 2 -anatase with high concentration (7.93 %) in 24 atoms are direct- and indirect-gap semiconductor, whereas the V-doped TiO 2 -rutile with high concentration (15.79 %) in 12 atoms is direct-gap semiconductor. The V-doped TiO 2 of both anatase and rutile produce the intermediate bands in the upper states. Ihe V-doped anatase produces intermediate band, which is 2.05, 2.04, 2.06 eV above the valence band for GGA+PBE, GGA+PW91 and LDA, respectively. Meanwhile the V-doped rutile producesintermediate band, which is 1.76, 1.82, 1.74 eV above the valence band for GGA+PBE, GGA+PW91 and LDA, respectively.