Abstract:
In this paper, the electronic structures and optical properties of light rare earth doped TiO
2 (101) surface are studied by first-principles method based on density functional theory. Simultaneously, the internal microscopic mechanisms are discussed. The results show that when the rare earth atoms are doped in TiO
2 (101) surface, the valence band maximum and conduction band minimum of doped systems induced by the doped atoms show a significant asymmetry, and the doped systems form some annexed P−type semiconductor or N-type semiconductor. Compared with the undoped system, the average band gaps of doped systems increase in different degrees, but some shallow impurity levels appeared in the band gap. The light absorption intensities of the doped systems that are formed by substituting rare earth atom for O atom or forming inserted atom are significantly higher than that of the doped systems formed by substituting rare earth atom for Ti atom. Among all the doped systems, the La@O13 system and Ce@O13 system have the strongest light absorption ability, which can be attributed to the generation of net magnetic moment and the formation of shallow impurity energy levels. Therefore, the generation and separation of electron hole pairs further improve the light absorption intensities of the doped systems in the visible region. These outcomes can provide a theoretical basis for the application and development of titanium dioxide in the field of optoelectronic devices.