Synthesis and characterization of alkali metal doped (Li, Na) ZnO thin films for photovoltaic applications

In this thesis, undoped and alkali metal (Li, Na) doped ZnO semiconductor thin films were obtained by using solution-based methods. The effect of the molar ratio of Li and Na on the physical properties of ZnO thin films was investigated using X-ray diffraction analysis (XRD), UV-Vis Spectrometer, scanning electron microscope (SEM) and Hall Effect measurement systems. ZnO thin film is a wide band gap semiconductor that has a polycrystalline hexagonal crystal structure with (002) preferred orientation. While it was observed that Na doping disrupted the crystal structure of ZnO, Li doping strengthened the crystal structure. Surface analyzes supported the XRD results. In addition, when the transmittance spectrum of Li-doped ZnO was examined, it was observed that Li-doped ZnO sample transmitted more light in the visible region. According to the electrical measurement result, it was observed that the charge carrier density of ZnO increased by the Li doping.