Al-doped and pure ZnO thin films elaborated by sol-gel spin coating process for optoelectronic applications

Pure and aluminum-doped zinc oxide thin films were grown by spin coating at room temperature. As a starting material, zinc acetate was used. The dopant source was aluminum nitrate; the dopant molar ratio was varied between 1 and 10%. Structural analysis reveals that all films consist of single hexagonal wurtzite phase ZnO, and a preferential orientation along c-axis. They have a homogeneous surface. The measurements show that the films are nanostructured. The transmittance is greater than 75% in the visible region. The band gap energy decreases with the addition of dopant (Al) in prepared thin films and the resistivity decreases significantly.