N,F-monodoping and N/F-codoping effects on the electronic structures and optical performances of Zn sub(2)GeO sub(4)

First-principles density-functional calculation has been performed to investigate the synergistic effects of N and F doping on the photocatalytic properties of Zn sub(2)GeO sub(4). Our results indicate that the presence of F facilitates the introduction of N by reducing the formation energy significantly. As N and F is codoped into Zn sub(2)GeO sub(4), the mobility of the charge carriers is more rapid due to the dispersive levels above the valence band. And with the narrowed band gap the optical absorption spectrum red-shifts into the ideal visible-light region. Thus, we propose that the codoping of N and F can be a promising strategy to promote the photocatalytic performances of Zn sub(2)GeO sub(4) under visible light.