Enhancement of the photoluminescence properties of Al2O3-core/SnO2-shell nanowires by annealing in an oxidative atmosphere

초록

We have fabricated Al2O3-core/SnO2-shell nanowires by thermal evaporation of Al powders and then coated Al2O3 nanowires with SnO2 by sputtering. We performed scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDXS), and photoluminescence (PL) spectroscopy to characterize the Al2O3-core/SnO2-shell nanowires. SEM analysis revealed that the nanowires were a few hundreds of nanometers in diameter and a few tens of micrometers in length. PL measurements at room temperature showed that Al2O3 nanowires had a strong yellow emission band centered at 580 nm and a weak broad green emission band centered at around 680 nm. The major emission of core-shell nanowires was found to be enhanced by annealing in an oxidative atmosphere but degraded in a reductive atmosphere. In addition, the origins of these changes by annealing are discussed.