Synthesis and ultraviolet luminescence properties of half-wall Al2O3 nanotube arrays

Abstract

Listen

Translate article

The ordered half-wall alumina nanotubes (HWANs) were synthesized in an oxalic acid solution via a two-step aluminium anodic oxidation process. Their optical properties are closely associated with the annealing temperature and time. The emission peak of HWANs appears at about 302 nm, which has probably resulted from the 1B → 1A transition. Compared with the Al2O3 powders, a distinct blue shift in the as-prepared HWANs occurs. A schematic drawing of the possible formation of HWANs is proposed and two possible mechanisms for the blue shift are discussed. It can be concluded that the electron transitions to the excited states at 5.3, 4.5 and 4.4 eV (F+ centres) account for the photoluminescence of HWANs at high annealing temperatures.