High sensitive MSM-configured UV photodetector based on c-axis-oriented Mg-doped ZnO thin films

The Mg-doped zinc oxide thin films with different concentrations were fabricated using the nebulizer spray pyrolysis process for UV photodetector applications in metal–semiconductor–metal (MSM) configuration. All the produced thin films were found to be polycrystalline type and have a hexagonal crystal structure exhibiting a strong c-axis orientation, according to X-ray diffraction examination. The scanning electron microscopy pictures exposes that the surface covered by flakes and grains type particles and well covered without any cracks. The water contact angle measurement notices diminishing of surface roughness. The maximum optical absorption of the film is approximately ~ 3.73% in the UV region for the 3% Mg-doped ZnO film. The optical band gap decreases with lower Mg concentrations and significantly increases at higher Mg doping concentrations. The photoluminescence spectra reveal the presence of defects such as zinc interstitials, oxygen vacancies, and anti-site defects in the obtained thin films. According to Hall Effect measurements, the produced thin films exhibit n-type conductivity with low resistivity (2.10 × 10⁻² Ω cm) and higher carrier concentrations (4.34 × 10¹⁹ cm⁻³) at a 3% Mg concentration. The fabricated thin-film photodetector showed a better response to UV exposure, with photocurrent increasing up to 10.629 µA. At a 3% Mg concentration, the photo-sensing capabilities, like detectivity, EQE, and responsivity, are enhanced.