Investigation of the porosity of thin Anodic Al2O3 films by interference of photoluminescence radiation

Abstract Photoluminescence emission spectra of thin (1–5 μm thick) Al 2 O 3 films formed by d.c. anodization of pure aluminium in 0.1 M oxalic acid have been investigated under the conditions of Lummer-Gehrke-type interference (in which the emmission angle is approximately equal to the total reflection angle). In this case, both p and s components of polarized light give additional (doublet) interference maxima owing to the inhomogeneity (porous structure) of the films. From the position of these doublets it is possible to determine the porosity coefficients of oxide films. The results are in good agreement with data obtained by electron microscopy.