Study on the Electronic Structure of ZnO
|School||Harbin University of Science and Technology|
|Keywords||ZnO First-principles band sturcture Metal-element dopant photocatalysis|
Zinc oxide is a direct band gap of semiconductor, owns good stability andcorrosion resistance. The price of zinc oxide is low and has good applicationprospect in photocatalysis area. But the band gap of zinc oxide is relatively wide,its low energy photons illuminate can inspire the light catalyst. So it can use theultraviolet visible light only. For this case, most scholars use doping to improvethe utilization rate of zinc oxide on the visible light. But the equipment for thiscost much. Therefore, this article calculates zinc oxide band structure, densitystates and light absorption curve basing on density functional theory and firstprinciples of metal doping. The results show that:The top of forbidden band of pure zinc oxide is the O2p electron orbitaland the bottom of it is the4s electron orbital. The width of forbidden band is0.736eV.Establish a supercell then optimize it. Calculate the band structure aftermetal element Al, Fe, Ni, Mg, Mn doped in zinc oxide, analyze their band gapchange.Get the forbidden band width is0.39eV,0.724eV,0.34eV,0.85eVand0.80eV, respectively.After Al, Fe, Ni, Mg, Mn doped in zinc oxide, the optical absorption areplotted graph comparing analysis showed: Al, Fe, Ni doped into the zinc oxideelements which are the long wavelength absorption curve direction in which theNi doped zinc oxide elements move sharpest; Mg, Mn element zinc oxide dopedoptical absorption curve shifts to shorter wavelengths, their red shift degree onarrangement: Ni/ZnO> Al/ZnO> Fe/ZnO> pure ZnO> Mn/ZnO> Mg/ZnO.After Al, Fe,Ni, Mg, Mn doped in zinc oxide, Ni makes the light catalyticeffect best, and followed by Al.