Tuning the crystallographic, morphological, optical and electrical properties of ZnO:Al grown by spray pyrolysis

• Solvents affect the crystallographic properties of spray pyrolysis grown ZnO:Al.
• Methanol leads to smooth films, water leads to hazy films.
• Organic precursors lead to lower resistivity, inorganic ones to higher resistivity.
• Short post-annealing in N2 improves conductivity.

In this contribution the effect of different deposition conditions on the physical properties of ZnO:Al grown by spray pyrolysis is outlined. In particular, it will be shown that the solvent composition affects the crystallographic orientation of the deposited films, as well as their roughness and electrical properties. Using water leads to higher resistive films than methanol. The choice of precursor salts also has an effect on the electrical properties, as using organic precursors leads to lower resistivity films. In both cases post-annealing helps to reduce the overall resistivity of the films. The reduction in resistivity will change depending on the initial deposition condition of the films, with lower values observed for films deposited at lower temperature. In optimum conditions a resistivity of 7 × 10− 3 Ω cm can be reproducibly achieved with inexpensive air blast nozzles at atmospheric pressure.