Nitrogen-doped ZnO films were deposited by RF magnetron sputtering in 75% of N-2/(Ar+N-2) gas atmosphere. The influence of substrate temperature ranging from room temperature (RT) to 300 degrees C was analyzed by X-ray diffractometry (XRD), spectrophotometry, X-ray photoelectron spectroscopy (XPS), secondary-ion mass spectrometry (SIMS) and Hall measurements setup. The XRD studies confirmed the hexagonal ZnO structure and showed that the crystallinity of these films increased with increasing substrate temperature (T-s). The optical studies indicate the average visible transmittance in the wavelength ranging 500-800 nm increases with increasing T-s. A minimum transmittance (9.84%) obtained for the films deposited at RT increased with increasing T-s to a maximum of 88.59% at 300 degrees C (500-800 nm). Furthermore, it was understood that the band gap widens with increasing T-s from 1.99 eV (RT) to 3.30 eV (250 degrees C). Compositional analyses (XpS and SIMS) confirmed the nitrogen (N) incorporation into the ZnO films and its decreasing concentration with increasing T-s. The negative sign of Hall coefficients confirmed the n-type conducting. (c) 2007 Elsevier B.V. All rights reserved.