This work reports the investigation of Au-NiO composite films, prepared by three different techniques: (i) all-sputtering, (ii) mixed sputtering and sol-gel, and (iii) all sol-gel. The Au-NiO films were deposited by (i) reactive DC magnetron sputtering from Au and Ni targets in an Ar + O-2 atmosphere, (ii) sputter-deposited nickel oxide films and gold nanoparticles deposited by the sol-gel and dip-coating methods, and (iii) gold and nickel oxide films prepared by sol-gel and dip-coating.In the first process (i), the Au content in the films was varied by changes in the DC power at the Au gun. In the second process (ii), the gold nanoparticles were obtained by dip-coating different sputtered-NiO films in an alcoholic solution of (AuCl3HCl)-H-. and Ti(OBu)(4). In the third process (iii), the films were dip-coated from a sol consisting of an alcoholic solution of NiCl2-6H(2)O, diethyalmine, acetylacetonate and (AuCl3HCl)-H-., followed by annealing.The morphology and the structure of the films were analyzed by means of X-ray diffraction, small angle X-ray scattering and electron microscopy. The optical properties were investigated by spectral absorbance in the range between 400 < lambda < 1000 nm wavelengths. (C) 2003 Elsevier B.V All rights reserved.