Abstract:CeO2 is a promising material for the utilization of solar light in photocatalytic reactions. However, the major obstacle for the studies is the lack of reliable methods to incorporate the desired elements such as nitrogen into the crystal lattice of CeO2. In this study, nitrogen-doped CeO2 thin film was synthesized by IBAD technique. With this technique, the nitrogen can be heavily and uniformly doped in CeO2 thin films. XPS analysis results clearly demonstrated the greatest N contraction of 25 mol% can be achieved in CeO2 thin films which was much higher than that via traditional methods. The high resolution N 1s spectrum shows that nitrogen dopants were uniformly doped into CeO2 lattice by substituting O via IBAD. The XRD results indicated ion bombardment on the growing film surface did not alter the crystal structure of the film by itself. Instead, the heavy nitrogen doping can induce smaller grain size of CeO2. The SEM images showed that with the increase of N doping, the surface became smoother with smaller particle size. The heavily nitrogen doping can also induce a red shift of the visible light absorbance from 380 to 450 nm.