Structure and Photoluminescence properties of TeO2-core/Ti02-shell nanowires

초록

TeO2-core/TiO2-shell composite nanowires were synthesized by a two–step process comprising thermal evaporation of Te powders and MOCVD of TiO2. Photoluminescence measurement showed that the TeO2 nanowires had an ultraviolet emission band centered at approximately 380 nm and a weak broad green emission band at approximately 560 nm. On the other hand, the TeO2/TiO2 composite nanowires exhibited a blue broad emission band centered at approximately 480 nm. In other words, the luminescence was red-shifted by TiO2 coating. The blue emission after TiO2 coating is not from the TeO2 cores but from TiO2 shells. The major emission from the composite nanowires was blue-shifted to the violet region and enhanced significantly by subsequent thermal annealing in an Ar atmosphere.