ZnO/Al2O3 core–shell nanorod arrays: growth, structural characterization, and luminescent properties

Abstract

We report an aqueous chemical method to fabricate well-aligned ZnO/Al 2 O 3 nanocrystal (NC) core–shell nanorod arrays (NRAs). Structural characterization showed that the shell layers are composed of α-Al 2 O 3 nanocrystals. Photoluminescence measurements showed the enhancement of near-band-edge (NBE) emission of ZnO NRAs due to the presence of Al 2 O 3 NC shells. The Al 2 O 3 NC shell layer resulting in the flat-band effect near the ZnO surface leads to a stronger overlap of the wavefunctions of electrons and holes in the ZnO core, further enhancing the NBE emission. This approach should be very useful in designing many other core–shell NRAs for creating varieties of high-efficiency optoelectronic devices.