Low temperature growth of highly crystallized ZnO:Al films by ultrasonic spray pyrolysis from acetylacetone salt

High-quality ZnO:Al films were deposited on glass substrates at a relatively low temperature of 300 degrees C by ultrasonic spray pyrolysis. Zn(acac)(2) and Al(acac)(3) acted as zinc and aluminum source, which dissolved in ethanol-water solution. The influences of aluminum concentration and vacuum annealing on microstructure. electrical and optical properties were investigated by XRD. SEM, EDS. four-point probe and visible spectroscopy. The experimental results shown that ZnO:Al films exhibit stronger (1 0 1) preferred orientation and have lenticular-like grain morphology. The resistivity as low as 4.3 x 10(-1) Omega cm for as-deposited films was obtained at the 4 at.% doping concentration, which can be decreased to 10(-2) Omega cm level by post-deposited vacuum annealing. The average transmittance of as-deposited films was nearly 80% in the visible range, and that of 4 at.% doped ZnO films reduced to 60% after vacuum annealing at 550-600 degrees C. (C) 2010 Elsevier B.V. All rights reserved.