Investigation of the features of the porous morphology of anodic alumina films at the initial stage of anodization

The work is devoted to the study of the porous structure formation of anodic alumina films at the initial stage of aluminium anodizing. SEM images of the surface morphology of the oxalic acid anodic films were analyzed. It was shown that at the initial stage, both major and minor pores are formed, the diameter ratio of which is about 1.16 and does not depend on the anodizing voltage. The results obtained indicate that the minor pores in the anodic films are located inside hexagonal cells composed of the major pores.

Optical properties of alumina films by sol gel acrylamide route

A new acrylamide route was applied to prepare alumina films by using aluminum chloride as a starting material and ammonium persulphate solution as the gelling agent. The XRD results show that the films are amorphous for the post anneals temperatures up to 300 °C, beyond this temperature; peaks corresponding to γ-Al2O3 are observed. XPS studies indicated the peaks corresponding to the Al 2p spectra of films after annealing at different temperatures. The FTIR spectra reveal absorption bands of Al-O and to lattice. The absorption co-efficient was 1014 cm- 1.Refractive index was in the range of 1.71 to 1.61 with increase of wavelength from 250-500 nm. Optical band gap value was around 5.40-5.75 eV with increase of annealing temperature.

FEATURES OF STIMULATED EMISSION OF A MEROCYANINE DYE IN THE PORES OF ANODIZED ALUMINUM

The results of the study of the spectral-luminescent properties and the generation of stimulated emission of merocyanine dye molecules in a porous aluminum oxide films are presented. The addition of silver nanoparticles to the porous aluminum oxide films leads to an increase in the absorption cross section and an increase in the quantum yield of dye fluorescence in the alumina films. However, in the alumina films with silver nanoparticles, the generation of stimulated emission of dye molecules was not detected. We also studied the effect of polymethyl methacrylate polymer deposited on the surface of the alumina films with a dye on the spectral-luminescent properties and generation of stimulated emission of this dye. An increase in the optical density in the absorption band of the dye and an increase in the fluorescence intensity in samples with a deposited polymethyl methacrylate film are observed. The generation threshold of polymethine dye is reduced by a factor of 40 in the porous aluminum oxide sample with polymethyl methacrylate.