Structural and electrical properties of aluminum-doped zinc oxide films prepared by sol–gel process

Aluminium-doped zinc oxide films were prepared through a non-alkoxide dip-coating technique from zinc acetate and aluminium nitrate in alcoholic solution. The doping concentration in the films varied between 0 and 8 at.%. The structural and electrical properties of the Al-doped zinc oxide (AZO) films are investigated in terms of the preparation conditions, such as the Al content, precursor solution, firing and annealing temperatures. The crystal structure of the AZO films is hexagonal wurtzite. In the present study, we found that the critical parameter determining the crystal quality is the aluminum concentration. The crystallographic orientation depends on the precursor system used in the film preparation regardless of the Al content and the heat-treatment temperature. The resistivity of the 1 at.%-doped AZO film is 2.5 × 10−3 Ω cm and depends mainly on the electronic mobility.