Measurement of the physical and electronic properties of ordered nanoporous alumina using XUV excitation spectroscopy

X-ray spectroscopy was used to probe the physical and electronic properties of highly ordered nanoporous alumina. X-ray excited optical luminescence and photoluminescence (PL) measurements showed a broad blue luminescence band that is due to a complex mixture of emission from F and F+ centres. To further understand the physics of the radiative transition, temperature dependence and full width half maximum data are presented. From photoluminescence excitation spectroscopy (PLE), it is suggested that the 6 eV band is associated with F centres in keeping with the previous literature, while the 5.2 eV band could be associated with the presence of F+ centres. There is no evidence of excitonic absorption in the PLE spectra of the nanoporous material and this may be due to the amorphous nature of nanoporous material. The x-ray absorption data showed a chemical shift in the L absorption edge of aluminium in porous alumina and also confirms the amorphous nature of nanoporous alumina.