Abstract

The optical properties of nanoporous alumina (Al 2O 3) prepared by electrochemical anodization of aluminum foils are studied. The samples show an ordered array of nanometric sized pores. Their reflectance spectra show an absorption edge in the UV that shifts into the visible with anodization temperature. A strong photoluminescence (PL) in the blue-green spectral range is also shown. The PL spectra shift in the same direction as the reflectance. The PL spectra were also measured at low temperatures. The results are best interpreted assigning the PL to oxygen vacancies. © 2007 WILEY-VCH Verlag GmbH & Co. KGaA.