Intrinsic and extrinsic luminescence of nanosize transition alumina powders

Luminescence spectroscopy in the VUV-visible range under electron-beam excitation and synchrotron radiation was applied to investigate electronic properties of alumina nanopowders, which were prepared using the combustion synthesis method. By varying reaction and post treatment conditions we were able to prepare phase pure samples and powders with mixtures of α- and γ-phases mainly. In addition to the well-known 7.6 eV luminescence of STE of α-alumina, all samples possessed complex emission bands in UV range (3–5 eV) which originate from intrinsic excitonic emissions and extrinsic electronic excitations.

► Luminescent spectroscopy of nanosized alumina powders was studied at 8 K. ► The crystalline structure of samples was analysed. ► Luminescent spectra, lifetimes and absorption onsets were discussed.