Aligned growth of ZnO nanowires and lasing in single ZnO nanowire optical cavities

Ordered ZnO nanowire arrays have been fabricated in N₂ background gas by catalyst-free nanoparticle-assisted pulsed-laser deposition. A single ZnO nanowire was collected in an electrode gap by dielectrophoresis. Under the optical pumping above an exciting laser (λ=∈355 nm) threshold of ∼ 334 kW/cm², ultraviolet lasing action in a single ZnO nanowire was observed at room temperature, indicating that the as-synthesized nanowires in pure N₂ background gas are of high quality. The crystalline facets of both ends of the nanowire acted to form an optical cavity. Therefore, the mode spacings corresponding to cavity lengths of the respective nanowires were observed in photoluminescence spectra.