Effect of oxygen flow rate on PECVD prepared ZnO thin films physical properties: experiments associated with DFT calculations

In this paper, we report on the deposition of zinc oxide thin films by the plasma enhanced chemical vapor deposition technique. The effects of oxygen flow rate on surface morphology, optic transmission, and gap energy are studied. The X-ray diffraction technique shows polycrystalline phases in the deposited material, the crystal structure is hexagonal, and the preferential orientation of crystal growth is in the (101) direction. The best optical transmission of zinc oxide is of the order of ∼ 89%, and a wide optical gap of ∼ 3.7 eV. To make a comparison with the present results and theoretical data, an ab initio calculation is carried out by the density functional theory method. To study the oxygen vacancies concentration effect on bandgap and optical transmission, we use three different configurations, namely ZnO0.97, ZnO0.94, and ZnO0.91. To confirm our experimental and calculated results, we compared them to those given in the literature.