Synthesis and characterization of Mg-doped ZnO thin-films for photovoltaic applications

Abstract

Zinc oxide (ZnO) has gained significant interest in the last few years due to its attractive properties for the transparent electronics industry, particularly due to its large direct band gap (Eg) ∼ 3.3 eV and exciton binding energy ∼60 meV. In this study, we report the elaboration and characterization of ZnO and Mg-doped ZnO (MZO) thin films with different Mg doping concentrations (0%, 2%, 3%, 4%, 5%, respectively).The Mg-doped ZnO (MZO) thin films were synthesized by the sol–gel immersive method on glass substrates, employing dehydrated zinc acetate, magnesium, ethanol as solvent, and MEA as stabilizer. The impact of Mg doping concentration on the structural and optical properties of the prepared films was examined using X-ray diffraction and UV visible spectroscopy, respectively. The (002) peak of the Mg-doped ZnO thin films is observed to be shifted to a higher angle as a consequence of Mg doping. The transmittance spectra reveal that Mg doping may increase the optical band gap of ZnO thin films. The band gap is adjusted from 2.95 eV to 3.10 eV by varying the Mg doping concentration between 2% and 5%.