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A DFT study on structural and electronic properties of n doped anatase TiO2 layers

In this research, the structural and electronic properties of N-doped anatase TiO2 layers were evaluated using the density functional theory (DFT). The results show that doping positions of N atoms cause different effects on the size and shape of unit cells of models. | JOURNAL OF SCIENCE OF HNUE Mathematical and Physical Sci. 2014 Vol. 59 No. 7 pp. 150-156 This paper is available online at http stdb.hnue.edu.vn A DFT STUDY ON STRUCTURAL AND ELECTRONIC PROPERTIES OF N-DOPED ANATASE TiO2 LAYERS Duong Quoc Van1 Nguyen Minh Thuy1 and Nguyen Huy Viet2 1 Faculty of Physics Hanoi National University of Education 2 Institute of Physics Vietnam Academy of Science and Technology Hanoi Abstract. In this research the structural and electronic properties of N-doped anatase TiO2 layers were evaluated using the density functional theory DFT . The results show that doping positions of N atoms cause different effects on the size and shape of unit cells of models. Calculated band structures of doped layers show the appearance of acceptor levels in the band-gaps and the decrease of band-gap values corresponds to pure layer values. Density of states DOS and projected density of states PDOS of doped layers show that N 2p orbital play the key role in the appearance of acceptor levels in forbidden bands. Ti 3d and O 2p orbitals still play the most important roles in the DOS of N-doped TiO2 layers. Keywords TiO2 layers N-doped DFT structural properties electronic structure. 1. Introduction Thin films have been used in many types of equipments in life science and technology. Various materials have been used to prepare thin films such as Si ZnO InGaZnO and more. Doped TiO2 films have been used in many kinds of technical applications for example gas sensors solar cells thin-film batteries gate electrodes for electronic devices and photocatalysts. In recent years most studies of doped TiO2 materials have concentrated on their photocatalytic activities especially for environmental pollution treatment solutions. Due to its wide band-gap doped TiO2 film s photocatalytic effect is negligible in the range of visible light. Visible photocatalytic effects can be available if the band-gap of doped TiO2 materials is narrowed. Impurity doping is the most commonly .