e-Cu共掺杂对SnO2薄膜光电特性的影响

he influence of Ce-Cu codoping on the microstructural and optoelectrical properties of SnO2 thin films prepared by sol-gel method has been investigated. Both Cu and Ce dopants are incorporated at substitutional sites , acting as the acceptors. With increasing the Ce content, the film grain size and optical band gap decrease, while the resistivity decreases at first and then increases due to the change of spatial trap distribution. The ultraviolet peak of the films can be attributed to the oxygen vacancies, while the blue emission at 470 nm belongs to the electron transition between 5d-excited state and 4f state of Ce3+ ion. Besides, the intensity of the visible emission peak is influenced by the Ce content. The first-principles calculations suggest that Ce-Cu co-dopants make the conduction band shift down and induce a fully occupied impurity band above the valance band, thus the band gap is decreased and the conductivity is improved.