Influence of the annealing atmosphere on the photoluminescence of ZnSe-core/In2O3-shell nanowires

Abstract

The influence of thermal annealing on the photoluminescence properties of the ZnSe-core/In2O3-shell nanowires prepared by a two-step process comprising the thermal evaporation of ZnSe powders and the sputter-deposition of In2O3 was investigated. The ZnSe nanowires were a few tens to a few hundreds of nanometers in diameter and up to a few hundreds of micrometers in length. Photoluminescence measurements showed that ZnSe nanowires had an emission band centered at around 630nm in the orange region. In contrast, ZnSe-core/In2O3-shell nanowires had a stronger emission band centered at around 560nm in the yellowgreen region. The major emission of the ZnSe nanowires was found to be blue-shifted and enhanced in intensity by coating them with In2O3. The major emission is shifted back to 630nm and further enhanced by annealing in a reducing atmosphere, whereas it is shifted back to ∼620nm and degraded in intensity by annealing in an oxidative atmosphere. The PL enhancement by annealing in a reducing atmosphere is mainly attributed to the formation of In interstitials in the ZnSe cores during the annealing process. © 2010 The Ceramic Society of Japan. All rights reserved.