Thin films of transparent conducting aluminum-doped ZnO have been deposited using a sol-gel process. The
dependence of electrical characteristics upon aluminum concentration in the films and upon post-deposition heat
treatment in vacuum was examined. The effect of changing the aluminum-to-zinc ratio from 0% to 4.5% (atomic)
and the heat treatment temperature in vacuum has been thoroughly investigated. Resistivities of (7-10) x 10 -4
f~ cm have been achieved for ZnO:AI films with AI/Zn ratios of 0.8 at.% heated to 450 °C in vacuum. Transmittance
in the visible region is above 90%. Similar results were obtained using aluminum chloride and aluminum nitrate as
the aluminum precursor.