Synthesis of ZnO nanowire heterostructures by laser ablation and their photoluminescence

ZnO nano-crystals have been paid a great attention as building blocks for the optoelectronic de-vices, such as an UV-LED. We have been succeeded in growing ZnO nanostructures, such as vertically-aligned ZnO nanowires and nanowalls, by a newly developed nanoparticle-assisted pulsed-laser deposition without using any catalyst. Depending on the growth condition a film-wire layer-structured ZnO and core/shell structured ZnO nanowires were synthesized on sapphire substrates. The room temperature photoluminescence spectrum of synthesized ZnO nanostructures exhibited an intrinsic UV emission and a defect-related visible emission.