Laser ablation coupled to mass quadrupole spectrometry (LAMQS) has been used to prepare thin films of aluminum oxide deposited on Si substrates starting from commercial Al2O3 polycrystalline targets. X-ray photoemission (XPS) and reflection electron energy loss spectroscopy ( REELS) have allowed the investigation of the electronic properties of the produced films. In particular, it was found that the Al/O atomic ratio assumes a value very near to 0.7 ( stoichiometric ratio) only for films deposited normally with respect to the target surface, while films grown at larger deposition angles are more rich in oxygen content. The composition, the mass density, the optical energy gap, the complex dielectric function and refraction index of the films have been calculated and compared with the results obtained from our starting target material and with the literature. The morphology of the deposited samples has been analyzed by the AFM technique. (C) 2008 Elsevier B. V. All rights reserved.