Aluminum-Doped Zinc Oxide Thin Films Deposited on Flexible Cellulose Triacetate Substrates Prepared by RF Sputtering

Transparent Al-doped ZnO thin films have been prepared by rf magnetron sputtering using on glass and a flexible cellulose triacetate substrates. The morphological, structural, chemical, optical and electrical properties were characterized by scanning electron microscopy, atomic force microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, ultra violet-visible spectroscopy (UV–Vis) and the Van der Pauw techniques respectively. The morphological analysis showed that the samples deposited on both substrates presented densely compacted grains with regular shapes, with roughness values of ~30 nm. The hexagonal wurtzite structure was obtained in both types of substrates with a preferred orientation (002), crystallite sizes of ~20 nm and with positive induced stress in the unit cell. The chemical analysis revealed the presence of Zn, O and Al atoms. Transmittance values of ∼80%, with an optical bandgap of ~3.50 eV, were obtained. The resistivity in both types of films was in the range ~10−3−10−2 Ω-cm with a mobility of ~3.6 cm2V−1s−1 and a carrier concentration of ~1020 cm−3.