Influence of ZnO encapsulation on the luminescence property of ZnGa2O4 nanowires

초록

ZnGa2O4-core/ZnO-shell nanowires were synthesized on (100) Si substrates by thermal evaporation of a mixture of ZnO and Ga2O3 powders followed by atomic layer deposition of ZnO. X-ray diffraction, scanning electron microscopy and transmission electron microscopy (TEM) analyses showed that the mean diameter and lengths of the core-shell nanowires were approximately 100 nm and a few tens of micrometers, respectively. The photoluminescence measurements showed that bare ZnGa2O4nanowires had a violet emission band centered at approximately 430 nm. In contrast, ZnGa2O4-core/ZnO-shell nanowires had a sharp near-band edge (NBE) emission band centered at approximately 380 nm as well as a broad deep-level (DL) emission band centered at approximately 590 nm, which is characteristic of ZnO. ZnGa2O4-core/ZnO-shell nanowires showed a higher intensity ratio of the NBE emission to DL emission than either ZnGa2O4 nanowires or ZnO nanowires. In addition, the origin of the enhancement of the luminescence in the ZnGa2O4nanowires by ZnO encapsulation is discussed.