Oxygen-induced physical property variation of deposited ZnO films by metal-organic chemical vapor deposition

► The microstructure of the film changes from nanorods form to continuous dense form as oxygen flow rate increases. ► With increase of oxygen discharge, the position of DLE in PL spectra demonstrates a significant shift, with transformation from VO to VZn. ► Qualitative percentage of surface VO from XPS data demonstrates an evident decrease trend from 43.7% (180 sccm) to 34.4% (250 sccm). ► The results indicate that higher O2-flow rate is able to promote OZn bond formation and reduce the number of VO.