Effect of Experimental Condition on Properties of Zinc Oxide Films Prepared by Sol-Gel Deposition with Ammonium Hydroxide as an Additive

In this work, we report on the study of undoped zinc oxide (ZnO) thin films prepared by sol-gel spin coating technique using the ammonium hydroxide as an additive. The effect of the precursor concentration and the annealing temperature on the optical and structural properties of the produced films is analyzed; we changed the precursor concentration and the annealing temperature from 0.1 M to 0.2 M and 400°C to 500°C with steps of 0.1M and 100°C, respectively. X-ray diffraction (XRD) results show that ZnO thin films are polycrystalline with a hexagonal structure and preferred growth orientations along the a-axis (100) and c-axis (002) from the substrate surface. The elaborated films have shown a high transparency (more than 75%) in the spectral range from 400 nm to 2000 nm. The optical band gap energy values of the ZnO thin films elaborated are located around 3.22 eV. Room temperature photoluminescence is dominated by a strong luminescence peak around 378 nm and a low-intensity peak around 477 nm.