Zn1-xMnxO thin films have been synthesized by chemical spray pyrolysis at different substrate temperatures in the range, 250-450 degrees C for a manganese composition, x = 15%, on corning 7059 glass substrates. The as-grown layers were characterized to evaluate their chemical and physical behaviour with substrate temperature. The change of dopant level in ZnO films with substrate temperature was analysed using X-ray photoelectron spectroscope measurements. The X-ray diffraction studies revealed that all the films were strongly oriented along the (002) orientation that correspond to the hexagonal wurtzite structure. The crystalline quality of the layers increased with the increase of substrate temperature up to 400 degrees C and decreased thereafter. The crystallite size of the films varied in the range, 14-24 nm. The surface morphological studies were carried out using atomic force microscope and the layers showed a lower surface roughness of 4.1 nm. The optical band gap of the films was similar to 3.35 eV and the electrical resistivity was found to be high, similar to 10(4) Omega cm. The films deposited at higher temperatures (>350 degrees C) showed ferromagnetic behaviour at 10 K. (C) 2008 Elsevier B.V. All rights reserved.