Effect of doping level and spray time on zinc oxide thin films produced by spray pyrolysis for transparent electrodes applications

In this paper, we present the results of optical, electrical and structural properties of zinc oxide (ZnO) semiconductors thin layers with various aluminium (Al) doping level and deposited at different spray time using the spray pyrolysis technique in atmospheric pressure. The study of optical properties from reflection and transmission spectra shows a high transmission value a band gap energy of about 3.33 eV and the reflection index is equal to 2.34 in the transparency range. The thickness is approximately equal to 1 μm. X-ray diffraction shows that these layers prepared at a substrate temperature of 380 °C, are well crystallized and oriented preferentially in the (0 0 2) direction. We also outperformed that ZnO:Al thin layers for a spray solution of 3% at.% Al doping rate and sputtered under 3600 s spray time, have a low value of resistivity of about 3 × 10-3 Ωcm. Hence this allows us to use those layers in photovoltaic and solar applications as transparent electrodes. © 2006 Elsevier B.V. All rights reserved.