Porous alumina membranes with ordered pore arrays were prepared electrochemically from Al in C2H2O4 or H2SO4. Photoluminescence measurements showed that a blue photoluminescence band occurred at wavelengths ranging from 400 to 600nm. This band originated from singly-ionized O vacancies (F+ centers) in the porous alumina membranes.

Preparation and Photoluminescence of Alumina Membranes with Ordered Pore Arrays. Y.Du, W.L.Cai, C.M.Mo, J.Chen, L.D.Zhang, X.G.Zhu: Applied Physics Letters, 1999, 74[20], 2951-3