Structural characteristics, low threshold ultraviolet lasing and ultrafast carrier dynamics in high crystalline ZnO nanowire arrays

Abstract

We report the structural characteristics and optical properties of well-aligned ZnO nanowire arrays. The quality of the produced nanowires is sufficiently good to act as efficient gain medium for stimulated emission. These nanowires exhibit ultraviolet lasing emission at room temperature with remarkably low optical excitation threshold of ∼60 μJ/cm 2. Furthermore, recombination emissions involving carrier dynamics of pure ZnO nanowires were investigated by the temperature-dependent time-resolved photoluminescence spectroscopy. Direct near-band-edge radiative recombination with a long lifetime of ∼1 ns from the ZnO nanowires was observed. Such pure ZnO nanowires are promising for applications in multifunctional photonic nanodevices.