The influence of post-annealing temperatures on XPS, XZ height of nanoparticles, and optical properties of Cu–Al doped ZnO films

In this article, using a radio frequency magnetron sputtering system at room temperature, Cu–Al doped ZnO films were deposited on quartz substrates. XPS studies have shown that the broad bands at around 932.5, 943, and 952 eV correspond to the Cu 2 P3/2 peak of Cu+1, Cu 2p3/2 of Cu+2, and Cu 2p1/2, respectively. In the case of Al2p3/2, the peak with binding energy 74.2 eV may be attributed to the presence of Al3+ oxide. The optical density, Dopt, of films annealed at 600 °C has a maximum value about of 0.25. Films annealed at 600 °C have a minimum value of the fractal dimensions, Df, about 2.65. It is observed that films annealed at 500 °C, have a maximum value of the single layer. The minimum value of dissipation factor occurred in films annealed at 500 °C. It can be seen that with doping Cu and Al atoms into ZnO films, the oxygen vacancies were nearly removed and the quality of films was increased; hence the porosity which is introduced in ZnO films can be removed by Cu–Al doping of ZnO films. Due to high evaporation in films annealed at 600 °C, they were rougher and they have a maximum value of RMS roughness at about 4.68 nm. Films annealed at 400 °C have a minimum value of dissipation factor.