Influence of In2O3 capping and annealing on the luminescence properties of Ga2O3 nanorods

Abstract

Ga2O3 nanorods were synthesized by thermal evaporation of GaN powders, and the influence of In2O3 capping and subsequent annealing on their luminescence properties was examined. The results of transmission electron microscopy and x-ray diffraction analyses indicated that the cores and shells of the annealed coaxial nanorods are monoclinic-structured single-crystal Ga2O3 and body-centered cubic-structured single-crystal In2O3, respectively. Photoluminescence (PL) measurements revealed that the blue emission band of Ga2O3 nanorods centered at approximately 460 nm was increased in intensity slightly by In2O3 coating and was increased in intensity further by subsequent thermal annealing. The PL peak was red-shifted from ∼460 to ∼530 nm by oxygen annealing. In contrast, the PL emission intensity of the nanorods was increased significantly and the PL peak was red-shifted from ∼460 to ∼590 nm by annealing in a reducing atmosphere. In addition, the origin of the PL intensity enhancement and of the PL peak shift by annealing is discussed.