Al-doped ZnO thin films by sol-gel method

Transparent and conductive high preferential c-axis oriented ZnO thin films doped with Al have been prepared by sol-gel method using zinc acetate and aluminium chloride as cations source, 2-methoxiethanol as solvent and monoethanolamine as sol stabilizer. Film deposition was performed by dip-coating technique at a withdrawal rate of 1.5 cm min(-1) on Corning 1737 glass substrate. The effect of dopant concentration, heating treatment and annealing in reducing atmosphere on the microstructure as well as on the electrical and optical properties of the thin films is discussed. The optical transmittance spectra of the films showed a very good transmittance, between 85 and 95%, within the visible wavelength region. The minimum resistivity of 1.3 X 10(-3) Omega cm was obtained for the film doped with 2 wt.% Al, preheated at 400 degreesC and post-heated at 600 degreesC, after annealing under a reduced atmosphere of forming gas. (C) 2003 Elsevier B.V. All rights reserved.