Experimental and ab-initio investigation of the microstructure and optoelectronic properties of FCM-CVD-prepared Al-doped ZnO thin films

In this research, pure and aluminium-doped zinc oxide (ZnO) thin films (5-50%) have been synthesized by the fine-channel mist chemical vapor deposition (FCM-CVD) technique. The microstructure and optoelectronic properties of the films have been characterized with the help of scanning electron microscope (SEM), X-ray diffraction (XRD), and UV-visible absorption (UV-Vis), respectively. The critical-doping (Al) concentration of ZnO was found to be 10%. Below this concentration of Al, the preferential orientation of the films was found to be along (002). Moreover, the films are in tensile states and the optical bandgap values found to be decreasing. For heavy doping concentration, the films are found to be in the compression states, and the optical bandgap increased with the Al concentration. To validate our experimental results, DFT calculations were performed to show and explain the origin of the variation of bandgap, tensile, and compression states.