Abstract
Transparent and conductive Al‐doped ZnO (AZO) films with thickness between 0.2 and 1.1 μm were deposited by sputtering at room temperature on glass and polyethylene terephthalate (PET) substrates. All films were polycrystalline with average crystallite size increasing when the film thickness was increased, being smaller for the layers grown on PET, which showed also a higher lattice distortion. For a same thickness, the optical band gap energy is found higher for the AZO layers deposited on PET, and such variation is related to the corresponding structural distortion. Besides, carrier mobility is found increasing and resistivity decreasing when the film thickness was increased, achieving a minimum value of 1.6 mΩ cm on glass and PET samples. An inverse relationship between the free carrier concentration and the mobility has been established, applying to the films grown on both substrates. With the thickest AZO layers, sheet resistance below 15 Ω sq^–1^ and average visible transmittance about 85% have been obtained by sputtering at room temperature on glass and PET substrates. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)