Effect of deposition rate on the structural, optical and electrical properties of Zinc oxide (ZnO) thin films prepared by spray pyrolysis technique

Zinc oxide (ZnO) thin films were deposited on glass substrates by spray pyrolysis technique decomposition of Zinc acetate dihydrate in an ethanol solution with various deposition rates, the ZnO thin films were deposited at 350 °C, the substrates were heated by using the solar cells method. The substrate was R217102 glass in a size of 30 cm × 7.5 cm × 0.1 cm. Nanocrystalline films with a hexagonal wurtzite structure with a strong (0 0 2) preferred orientation were observed at all sprayed films. The maximum value of grain size (21.91 nm) is attained of sprayed films with 30 ml. The decrease of the strain of ZnO films is probably due to an improvement of the crystallinity of the films. The average transmittance of all films is about 90 – 95% measured by UV – vis analyzer. The band gap energy varies from 3.265 to 3.286 eV was affected by deposition rates lying between 10 and 35 ml. The electrical resistivity of the films decreased from 0.394 to 0.266 (Ω cm). The best results are achieved in sprayed films between 25 and 30 ml.